Table of Contents - Ohio Medical

1111 Lakeside Drive, Gurnee, IL 60031-4099 Phone: 800-448-0770 Fax: 847-855-6300 www.ohiomedical.com

TABLE OF CONTENTS Technical

Selecting a Vacuum System Sizing a Medical Vacuum System Vacuum System Exhaust Selecting an Air System Sizing an Air Compressor System Special Considerations Full Load Amps for Vacuum and Air Compressor Packages Suggested Medical Gas Master Alarm Points (For level 1 facilities) Medical Gas Equipment Mounting Height Detail Manifold Sizing Medical Gas Cylinder Data Conversion Chart – Vacuum ACFM / SCFM Common Conversions Flow Conversion Chart Volume Conversion Chart Temperature Conversion Chart Miscellaneous Conversions Pressure Conversion Chart Altitude Compensation for Vacuum Receiver Sizing Technical White Papers from Ohio Medical Corporation ACFM vs. SCFM vs. ICFM Pressure Drop in Air Piping Systems Affects of Altitude on Vacuum Systems Systems Limited Warranty Pipeline Warranty

TRUSTED BRANDS OF OHIO MEDICAL

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SELECTING A VACUUM SYSTEM There are several considerations in selecting a Medical/Surgical Vacuum System. In addition to physical size, expense, and site limitations, capacity is the primary issue. The required capacity, or flow at a given vacuum level, most generally 19” Hg Gauge, is also referred to as Calculated Peak Demand. Click here for the worksheet used to determine Calculated Peak Demand for a typical hospital. You will notice that the categories on the worksheet coincide with various areas in the hospital. Because of the manner in which the space is used, the value given for flow is either per room, per bed, or per outlet. For example, in areas where only one procedure will be performed, such as surgery, we use a per room value. In areas where there may be several uses simultaneously and the possibility of vast fluctuations in use, such as a recovery suite, we calculate the demand per bed. You will also notice the term “Simultaneous Use Factor”. This is a value given to the likelihood that the full demand will exist in a particular area at any given time. The most critical areas, such as surgery, will have the highest likelihood and therefore the greatest value. To use the worksheet, start by filling in the quantities of each area in the left-hand column. Keep in mind to tally these figures correctly; either per room, bed or outlet. Also be certain to account for all of the outlets which are part of the proposed system. Some outlets may be easy to overlook and some departments in the facility may be known by a slightly different name. If you encounter an area in the facility that is not listed on the worksheet, categorize it based on what procedures are performed in that area. With all of the areas accounted for, multiply each quantity by the given Design Flow value, and then multiply by the Simultaneous Use Factor. Write the value in the right hand column for each line. Finally, total the values for all of the lines at the bottom of the sheet. This value is the Calculated Peak Demand, expressed in Standard Cubic Feet per Minute at a vacuum level of 19”Hg Gauge. Having tallied the Calculated Peak Demand, you must adjust for any abnormal conditions. High elevation, operation on 50 Cycle current or unusual ambient temperatures can affect performance. If considering future expansion, you may opt for a system with a control package which will allow for an additional pump to be added later. When the Calculated Peak Demand exceeds the capacity of a 10 Horsepower pump, consider using a triplex or quadruplex system rather than duplex. For example, if you have chosen a 15Hp duplex system, also consider a 7.5 Hp triplex version where two of the three pumps will meet the Calculated Peak Demand. Demand for Medical/Surgical Vacuum in a typical facility varies widely in the course of a day, and in times of low demand, a 7.5 Hp pump will be required to operate as opposed to a 15 Hp pump. Each pump on the system is controlled by a separate vacuum switch, allowing more efficient operation and reducing current spikes caused by the in-rush as the larger motors start. In many cases, the initial expense of the multiplex system is also lower. A dedicated Waste Anesthetic Gas Evacuation system is best served by use of a separate simplex or duplex vacuum system of either the Water Sealed Liquid Ring or Dry Running Rotary Vane style. Pumps lubricated or sealed with oil are not to be used for such a system.

TM

www.ohiomedical.com

1111 Lakeside Drive, Gurnee, IL 60031-4099 Phone: 800-448-0770 - Fax: 847-855-6300

www.squire-cogswell.com An Ohio Medical Corporation Brand

Project:

Date:

Calculated Peak Demand for a Medical Surgical Vacuum System in a Typical Short Term General Hospital Design Flow in SCFM (Free Air) Simultaneous Per Per Per Use Factor Room Bed Outlet %

Qty Medical Gas Vacuum Outlet Locations

Total

ANESTHETIZING LOCATIONS: Specialized Surgeries (Open Heart, Organ Transplant) Major / Outpatient OR Cystoscopy / Endoscopy Delivery Room Emergency Operating Room Cardiac Catheterization Other Anesthetizing Areas (Minor O.R., Induction Rooms, etc .) Waste Anesthetizing Gas Evacuation

4.0 3.5 2.0 1.0 3.0 1.0

100 100 100 100 100 10

0 0 0 0 0 0

1.0 2.0

50 100

0 0

50 50 75 100 50 50 25 10

0 0 0 0 0 0 0 0

10 20 10 10 50 10 10 10 10 10

0 0 0 0 0 0 0 0 0 0

20 10 10 10 10

0 0 0 0 0

ACUTE CARE (NON-ANESTHETIZING LOCATIONS): Post Operative Recovery Room O.B. Recovery Room Intensive Care Units (Except Cardiac) Emergency Room (Trauma, Cardiac) Cardiac Intensive Care Neonatal I.C.U. Special Procedure (X-Ray,Dialysis,Radiology) Surgical Excision Room

3.0 2.0 2.0 1.0 2.0 1.0 1.5 1.0

SUBACUTE PATIENT CARE AREAS: Normal Nursery Premature Nursery Respiratory Care Labor/Birthing Patient Room (Surgical) Patient Room (Medical) Exam & Treatment Rooms ER (Cast Room, OB/GYN) Pre-Op Holding Stress Test EKG & EEG

1.0 1.0 1.5 1.0 1.5 1.0 1.0 1.0 1.0 1.0

OTHER AREAS: Autopsy / Morgue Central Supply / Sterile Equipment Repair,Calibration & Teaching Medical Lab / Pharmacy Anesthesia/Workroom

2.0 1.5 1.5 1.0 1.5

Total Estimated Peak Flow (In SCFM @ 19" Hg) Ohio Medical Corporation 1111 Lakeside Drive - Gurnee, IL 60031-4099 Ph: 800-448-0770 - Fax: 847-855-6300 Visit us on our website: www.ohiomedicall.com 550611 (Rev.4) 06/2006

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SELECTING AN AIR SYSTEM There are several considerations in selecting a Medical Compressed Air System. In addition to physical size, expense, and site limitations, capacity is the primary issue. The required capacity, or flow at a given pressure, most generally 50 PSIG, is also referred to as Calculated Peak Demand. Click here for the worksheet to determine Calculated Peak Demand for a typical hospital. You will notice that the categories on the worksheet coincide with various areas in the hospital. Because of the manner in which the space is used, the value given for flow is either per room, per bed, or per outlet. For example, in areas where only one procedure will be performed, such as surgery, we use a per room value. In areas where there is the possibility of vast fluctuations in use, such as an ICU, we calculate the demand per bed. You will also notice the term “Simultaneous Use Factor”. This is a value given to the likelihood that the full demand will exist in a particular area at any given time. The most critical areas, such as surgery, will have the highest likelihood and therefore the greatest value. To use the worksheet, start by filling in the quantities of each area in the left-hand column. Keep in mind to tally these figures correctly; either per room, bed or outlet. In the case of Ventilators, it is important to consider the type and requirements of each unit the facility intends to operate. Ventilators powered by medical air require considerable capacity and must be accounted for. Also be certain to account for all of the outlets which are part of the proposed system. Some outlets may be easy to overlook and some departments in the facility may be known by a slightly different name. If you encounter an area in the facility that is not listed on the worksheet, categorize it based what procedures are performed in that area. With all of the areas accounted for, multiply each quantity by the given Design Flow value, and then multiply by the Simultaneous Use Factor. Write the value in the right hand column for each line. Finally, total the values for all of the lines at the bottom of the sheet. This value is the Calculated Peak Demand, expressed in Standard Cubic Feet per Minute at a pressure of 50 Pounds per Square Inch Gauge. Having tallied the Calculated Peak Demand, you must adjust for any abnormal conditions. High elevation, operation on 50 Cycle current or unusual ambient temperatures can affect performance. If considering future expansion, you may opt for a system with a control package, which will allow for an additional compressor to be added later. When the Calculated Peak Demand exceeds the capacity of a 15 Horsepower compressor, consider using a triplex or quadruplex system rather than duplex. For example, if you have chosen a 20 Hp duplex system, also consider a 7.5 Hp triplex version where two of the three compressors will meet the Calculated Peak Demand. Demand for Medical Air in a typical facility varies, and in times of low demand, a 7.5 Hp compressor will be required to operate as opposed to a 20 Hp compressor. Each compressor on the system is controlled by a separate pressure switch, allowing more efficient operation and reducing current spikes caused by the in-rush as the larger motors start. In many cases, the initial expense of the multiplex system is also lower. Please peruse the Accessories tab of the Medical Air Systems section for optional types of air dryers and other related accessories. The Healthcair® Treatment Module is a fabricated package incorporating dual dryers, filters, regulators, and monitors. It can be used to upgrade existing installations.

TM

www.ohiomedical.com



Project:

Date:

Calculated Peak Demand for a Medical Air System in a Typical Short Term General Hospital Design Flow in SCFM (Free Air) Simultaneous Per Per Per Per Use Factor Unit Room Bed Outlet % ANESTHETIZING LOCATIONS:

Qty Medical Air Outlet Locations

Totals

Special Surgery (Open Heart, Organ 0.5 0.5 0.5 0.5 0.5 1.0 0.5

Transplant, Ortho)

Major / Outpatient Surgery Minor Surgery Emergency Surgery Cardiac Catherization Endoscopy / Cytoscopy Delivery Room / C-Section

100 100 75 50 50 10 100

0 0 0 0 0 0 0

50 25 50 50 10 75 10 10 50 50

0 0 0 0 0 0 0 0 0 0

50 25 10 10 50 10 50 50 50

0 0 0 0 0 0 0 0 0

10 10 10

0 0 0

ACUTE CARE LOCATIONS: Recovery Room/Surgical Recovery Room - OB ICU/CCU & Pediatric I.C.U. Emergency Room (Trauma, Cardiac) Anesthesia Workroom Neonatal ICU Pre-Op Holding Dialysis Unit, Radiology Ventilators Adult* Ventilators Infants*

2.0 0.5 2.0 2.0 1.5 1.5 1.5 0.5 3.5 3.5

SUBACUTE CARE LOCATIONS: Pediatric Croup Tents** Nursery Full Term & Isolation ER (Cast Room, OB/GYN) Patient Rooms (Medical & Surgical) EEG & EKG Exam & Treatment Respiratory Care Pulmonary Function Lab Birthing & LDRP

2.0 0.5 1.0 0.5 1.0 1.0 1.0 1.0 1.0

OTHER: Respiratory Care Workroom Autopsy / Morgue Equipment Repair

1.5 1.5 1.5

Total Estimated Peak Flow (In SCFM @ 50 PSIG) * Important! You must consult with respiratory therapy personnel concerning the maximum number of ventilators that could be used at one time and the average flow rates for each ventilator. DO NOT CALCULATE your total peak requirements without this information. ** If powered by Medical Air

Ohio Medical Corporation 1111 Lakeside Drive - Gurnee, IL 60031-4099 Ph: 800-448-0770 - Fax: 847-855-6300 Visit us on our website: www.ohiomedical.com 550611 (Rev.4) 06/2006

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Vacuum System Exhaust Installation

Notes: Piping Connections: 1. All piping connections shall be checked for tightness by the installing contractor prior to starting the system. 2. Exhaust Piping and fittings represented by dashed lines are to be furnished and installed by the contractor. 3. Exhaust from oil reservoir shall be collected to a single stack, run to outside air with the discharge line turned down and screened. 4. Vent / Exhaust should be piped by installer in accordance with C.G.A. P2.1 recommendations or N.F.P.A. 99 standards. If a drop in a horizontal run of exhaust piping is present, then a drip leg will be required. For recommendations on exhaust pipe sizing consult Ohio Medical Engineering @ 1-800-448-0770. Electrical Connections: 5. All the electrical connections shall be checked for tightness by the installing contractor prior to starting the system. 6. Electrical contractor is to furnished and install wiring of proper size and type per NEC code. Miscellaneous: 7. Inlet (non-braided) and discharge (braided) flexible connectors, vibration pads and system isolation valves are shipped separately. Accessories are shipped inside the system crate and designated with an orange label. Accessories to be installed by contractor.

P/N 255356 (Rev.3) 02/2006

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SPECIAL CONSIDERATION The performance data for Medical Air and Vacuum Systems is based upon standard atmospheric conditions. Significant deviations from these standards must be accounted for in proper selection of the systems. Elevation If the site is above sea level, the reduced barometric pressure of the atmosphere affects the performance of Medical/Surgical Vacuum Systems in two ways. First, the maximum vacuum level obtainable is reduced. In addition, the capacity or flow characteristics of a vacuum pump at a given vacuum level are reduced. Base on their performance curves, different types of vacuum pumps react differently. Please consult the factory for help in selection of systems for higher altitudes. Temperature These systems are intended to be installed indoors, in a controlled climate. Temperatures should never approach freezing or exceed 104 degrees Fahrenheit. These extremes will affect overall system performance, maintenance intervals and equipment life as well. In addition, these systems will generate heat, and this heat load must be considered when designing the mechanical space in which they are to be installed. To calculate the heat generated by the air or vacuum system, use Brake Horsepower of the system multiplied by 2,545 BTU/Hr. ___ BHP x 2,545 BTU/Hr = _____ BTU/Hr generated by the system. In the case of multiplex systems, use the horsepower value of the units that are intended to operate under normal conditions. If you do not know the Brake Horsepower requirement, use the nameplate Horsepower value. This formula can also be used to calculate the heat load that a totally recirculated, water sealed, liquid ring pump will contribute to the cooling water loop or chiller. Make-Up Water and Cooling Water Temperature Liquid ring vacuum pumps using water as a sealing fluid are subject to decreased performance if the water temperature is substantially greater then 60 degrees Fahrenheit. Inertia Bases When installed above ground, it may be advisable to mount reciprocating compressors on an inertia base. This will eliminate the transfer of vibration and related noise to the structure. Rotary vane and Liquid ring style units do not require inertia bases. Seismic Certification Most systems can be certified for use in various seismic zones. Please consult the Medical Sales Department for help in selecting a system.

TM

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Full Load Amps for Rotary Vane Vacuum Systems Lubricated Rotary Vane Vacuum Pumps

Model Number S200B S300LB S300B S500LB S500B S750B S1000B

Model Number S200B S300LB S300B S500LB S500B S750B S1000B S1500B S2000B S2500B

Simplex Systems System Full Load Amps H.P. 208 230 460 2 8.8 7.2 4.1 3 12.0 8.8 4.9 3 12.0 8.8 4.9 5 18.5 13.8 7.4 5 18.5 13.8 7.4 7.5 26.3 19.6 10.3 10 33.2 26.0 13.5

H.P. 2 3 3 5 5 7.5 10 15 20 25

Model Number S500B S750B S1000B S1500B S2000B S2500B

Duplex Systems System Full Load Amps 208 17.6 24.0 24.0 37.0 37.0 52.6 66.4 98.6 126.2 158.4

230 14.4 17.6 17.6 27.6 27.6 39.2 52.0 86.0 110.0 138.0

Model Number S500B S750B S1000B S1500B S2000B S2500B

460 8.2 9.8 9.8 14.8 14.8 20.6 27.0 44.0 56.0 70.0

H.P. 5 7.5 10 15 20 25

H.P. 5 7.5 10 15 20 25

Triplex Systems System Full Load Amps 208 230 460 55.5 41.4 22.2 78.9 58.8 30.9 99.6 78.0 40.5 147.9 129.0 66.0 189.3 165.0 84.0 237.6 207.0 105.0

Quad Systems System Full Load Amps 208 73.8 105.0 132.6 197.0 252.2 316.6

230 55.0 78.2 103.8 171.8 219.8 275.8

460 29.4 41.0 53.8 87.8 111.8 139.8

Oil-less Rotary Vane Vacuum Pumps

Model Number D100B D150B D200B D300B D500LB D500B D750B D1000B

Simplex Systems System Full Load Amps H.P. 208 230 460 1 5.8 5.2 3.1 1.5 7.9 7.0 4.0 2 8.8 7.8 4.4 3 12.0 10.6 5.8 5 18.5 16.2 8.6 5 18.5 16.2 8.6 7.5 26.3 23.0 12.0 10 33.2 29.0 15.0

Model Number D100B D150B D200B D300B D500LB D500B D750B D1000B

H.P. 1 1.5 2 3 5 5 7.5 10

Duplex Systems System Full Load Amps 208 230 460 11.6 10.4 10.4 15.8 14.0 14.0 17.6 15.6 15.6 24.0 21.2 21.2 37.0 32.4 32.4 37.0 32.4 32.4 52.6 46.0 46.0 66.4 58.0 58.0

*FLA amps listed are approximate

www.squire-cogswell.com

1111 Lakeside Drive, Gurnee, IL 60031-4099 Phone: 800-448-0770 - Fax: 847-855-6300 1 of 4

www.ohiomedical.com

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Full Load Amps for Rotary Claw Vacuum Systems

Model Number C300B C500B C750B C870B C1000B C1500B

Model Number C300B C500B C750B C870B C1000B C1500B

Simplex Systems System Full Load Amps H.P. 208 230 460 3 5 7.5 8.7 10 15

5.6 8.5 11.9 13.7 15.0 18.5

C300B C500B C750B C870B C1000B C1500B

Duplex Systems System Full Load Amps H.P. 208 230 460

Model Number

H.P.

C300B C500B C750B C870B C1000B C1500B

3 5 7.5 8.7 10 15

3 5 7.5 8.7 10 15

10.8 18.4 26.6 30.0 30.5 N/A

21.6 36.8 53.2 60.0 61.0 N/A

10.2 16.0 22.8 26.4 29.0 36.0

Model Number

Triplex Systems System Full Load Amps H.P. 208 230 460

20.4 32.0 45.6 52.8 58.0 72.0

11.2 17.0 23.8 27.4 30.0 37.0

3 5 7.5 8.7 10 15

32.4 55.2 79.8 90.0 91.5 N/A

30.6 48.0 68.4 79.2 87.0 108.0

16.8 25.5 35.7 41.1 45.0 55.5

Quad Systems System Full Load Amps 208 230 460 43.0 73.4 106.2 119.8 121.8 N/A

40.6 63.8 91.0 105.4 115.8 143.8

22.2 33.8 47.4 54.6 59.8 73.8


Ohio Medical Corporation - 1111 Lakeside Drive, Gurnee, IL 60031-4099 - Phone: 800-448-0770 - Fax: 847-855-6300 2 of 4

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Full Load Amps for Liquid Ring Vacuum Systems Water Sealed Partial or Total Recirculation

Model Number LR3B LR5B LR75B LR10B LR15B LR20B LR25B

Simplex Systems System Full Load Amps H.P. 208 230 460 3 5 7.5 10 15 20 25

Model Number

H.P.

LR3B LR5B LR75B LR10B LR15B LR20B LR25B

3 5 7.5 10 15 20 25

9.5 15.0 24.0 30.9 47.0 61.0 77.0

8.8 14.6 19.8 25.8 41.0 53.0 63.0

4.9 7.8 10.4 13.4 21.0 27.0 32.0

Duplex Systems System Full Load Amps 208 230 460 19.0 30.0 48.0 61.8 94.0 122.0 154.0

17.6 29.2 39.6 51.6 82.0 106.0 126.0

9.8 15.6 20.8 26.8 42.0 54.0 64.0

Model Number

H.P.

LR10B LR15B LR20B LR25B

10 15 20 25

Model Number

H.P.

LR5B LR75B LR10B LR15B

5 7.5 10 15

Triplex Systems System Full Load Amps 208 230 460 92.7 141.0 183.0 231.0

77.4 123.0 159.0 189.0

40.2 63.0 81.0 96.0

Quad Systems System Full Load Amps 208 230 460 59.8 95.8 123.4 187.8

58.2 79.0 103.0 163.8

58.2 79.0 103.0 163.8



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Full Load Amps for Oil-Less Air Compressor Systems

Model Number AS200B AS300B AS500B

Model Number AS200B AS300B AS500B AS750B AS1000B AS1500B

Simplex Systems Full Load Amps H.P. 208 230 460 2 3 5

8.8 12.0 18.5

7.8 10.6 16.2

Model Number

4.4 5.8 8.6

AS500B AS750B AS1000B AS1500B

Duplex Systrems Full Load Amps H.P. 208 230 460 2 3 5 7.5 10 15

17.6 24.0 37.0 50.4 63.6 94.4

15.6 21.2 32.4 46.0 58.0 86.0

8.8 11.6 17.2 24.0 30.0 44.0

Triplex Systems Full Load Amps H.P. 208 230 460 5 7.5 10 15

Model Number

H.P.

AS750B AS1000B AS1500B

7.5 10 15

26.4 75.6 95.4 141.6

23.4 69.0 87.0 129.0

13.2 36.0 45.0 66.0

Quad Systems Full Load Amps 208 230 460 100.6 127.0 188.6

91.8 115.8 171.8

47.8 59.8 87.8

Full Load Amps for Oil-Less Air Compressor Systems Simplex Systems Model Number A200B A300B A500B A750B A1000B A1500B

Model Number A200B A300B A500B A750B A1000B A1500B A2000B A2500B A3000B

H.P. 2 3 5 7.5 10 15

H.P. 2 3 5 7.5 10 15 20 25 30

Triplex Systems

Full Load Amps 208 8.8 12.0 18.5 26.3 33.2 49.3

230 7.8 10.6 16.2 23.0 29.0 43.0

Model Number A500B A750B A1000B A1500B A2000B A2500B A3000B

460 4.4 5.8 8.6 12.0 15.0 22.0

Duplex Systrems Full Load Amps 208 17.6 24.0 37.0 52.6 66.4 98.6 126.2 158.4 186.0

230 15.6 21.2 32.4 46.0 58.0 86.0 110.0 138.0 162.0

Model Number A750B A1000B A1500B A2000B

460 8.8 11.6 17.2 24.0 30.0 44.0 56.0 70.0 82.0

H.P. 5 7.5 10 15 20 25 30

H.P. 7.5 10 15 20

Full Load Amps 208 55.5 78.9 99.6 147.9 189.3 237.6 279.0

230 48.6 69.0 87.0 129.0 165.0 207.0 243.0

460 25.8 36.0 45.0 66.0 84.0 105.0 123.0

Quad Systems Full Load Amps 208 105.0 132.6 197.0 252.2

230 91.8 115.8 171.8 219.8

460 47.8 59.8 87.8 111.8



SUGGESTED MEDICAL GAS MASTER ALARM POINTS


FOR LEVEL 1 FACILITIES


MECHANICAL ROOM

MEDICAL GAS ROOM

MASTER ALARM #1 MAY BE LOCATED IN SECURITY (Requires 24 Hours/Day Surveillance)

MASTER ALARM #2 MAY BE LOCATED IN ENGINEERING DEPARTMENT/AREA Source/Mainline Isolation Valve

Typical Oxygen (O2), Medical Air (Air), Nitrous Oxide (N2O), Carbon Dioxide (CO2) Installation

Source/Mainline Isolation Valve


261920* Actuating Pressure Switch (Reserve In Use, Activate HP Cylinders set at 85 PSIG)

Typical Nitrogen (N2) Installation

Check Valve Located in Pigtail

SUGGESTED ALARM POINTS FOR: MEDICAL AIR COMPRESSOR (All Types)


RESERVE COMPRESSOR RUNNING 5.1.9.5.4(1) / 5.1.3.5.14.5 (Termination point located in compressor control panel) MAINLINE PRESSURE HIGH 5.1.9.2.4(7) Regulator

(Termination point from mainline pressure switch)

261921 Actuating Pressure Switch ("Reserve Low", 500 PSIG)

MAINLINE PRESSURE LOW 5.1.9.2.4(7) (Termination point from mainline pressure switch)

SUGGESTED ALARM POINTS FOR: MEDICAL/SURGICAL VACUUM PUMPS

CARBON MONOXIDE HIGH 5.1.9.4.5(2) / 5.1.3.5.15(2)

RESERVE VACUUM PUMP RUNNING

DEW POINT HIGH 5.1.9.2.4(10) / 5.1.3.5.15(1)

5.1.3.6.8 / 5.1.9.2.4(9) / 5.1.9.5.2 / 5.1.9.5.4(4) (Termination point located in vacuum control panel) MAIN LINE VACUUM LOW 5.1.9.2.4(8) (Terminal point from main line vacuum switch)

WASTE ANESTHETIC GAS VACUUM PUMPS

Also, For Reciprocating (Piston type) Compressors HIGH TEMPERATURE 5.1.3.5.14.3 / 5.1.9.5.4(9) / 5.1.3.5.14.4(1) (Termination point located in compressor control panel)

(Termination point located in vacuum control panel) MAINLINE EVACUATION LOW

(Termination point located in compressor control panel)

Also, For Liquid Ring Compressors:

5.1.9.5.2 / 5.1.3.7.4.1 / 5.1.9.2.4(9) / 5.1.9.5.4(5)

5.1.9.2.4(8)

(Termination point from main line vacuum switch)

MANIFOLDS WITH RESERVE


RECEIVER FLOODED (see note #1) 5.1.3.5.14.1 / 5.1.9.5.4(7)


SUGGESTED ALARM FUNCTIONS FOR:

(Termination point from CO monitor)

RECEIVER FLOODED 5.1.3.5.14.1 / 5.1.9.5.4(7) (Termination point located in compressor control panel) HIGH WATER SEPARATOR 5.1.3.5.14.2 / 5.1.9.5.4(8) (Termination point located in compressor control panel)

CYLINDER BANK CHANGEOVER 5.1.9.2.4(1) / 5.1.3.4.12.9(1)

SUGGESTED ALARM FUNCTIONS FOR: MANIFOLDS WITHOUT RESERVE CYLINDER BANK CHANGEOVER 5.1.9.2.4(1) / 5.1.3.4.10.6 (Termination point located in power supply) MAINLINE PRESSURE HIGH 5.1.9.2.4(7) (Termination point from mainline pressure switch) MAINLINE PRESSURE LOW 5.1.9.2.4(7) (Termination point from mainline pressure switch)

(Termination point located in power supply) RESERVE IN USE 5.1.9.2.4(3) / 5.1.3.4.15.5 / 5.1.3.4.12.9(3) (Terminal point from actuating pressure switch 261920*) RESERVE LOW 5.1.3.4.12.9(4) / 5.1.9.2.4(5) (Terminal point from actuating pressure switch 261921*) MAINLINE PRESSURE HIGH 5.1.9.2.4(7) (Termination point from mainline pressure switch) MAINLINE PRESSURE LOW 5.1.9.2.4(7) (Termination point from mainline pressure switch)





MECHANICAL ROOM

MEDICAL GAS ROOM

MASTER ALARM #1 MAY BE LOCATED IN SECURITY (Requires 24 Hours/Day Surveillance)

MASTER ALARM #2 MAY BE LOCATED IN ENGINEERING DEPARTMENT/AREA Source/Mainline Isolation Valve

Typical Oxygen (O2), Medical Air (Air), Nitrous Oxide (N2O), Carbon Dioxide (CO2) Installation



261920* Actuating Pressure Switch (Reserve In Use, Activate HP Cylinders set at 85 PSIG)


Check Valve Located in Pigtail

SUGGESTED ALARM POINTS FOR: MEDICAL AIR COMPRESSOR (All Types)


RESERVE COMPRESSOR RUNNING 5.1.9.5.4(1) / 5.1.3.5.14.5 (Termination point located in compressor control panel) MAINLINE PRESSURE HIGH 5.1.9.2.4(7) Regulator

(Termination point from mainline pressure switch)

261921 Actuating Pressure Switch ("Reserve Low", 500 PSIG)

MAINLINE PRESSURE LOW 5.1.9.2.4(7) (Termination point from mainline pressure switch)

SUGGESTED ALARM POINTS FOR: MEDICAL/SURGICAL VACUUM PUMPS

CARBON MONOXIDE HIGH 5.1.9.4.5(2) / 5.1.3.5.15(2)


DEW POINT HIGH 5.1.9.2.4(10) / 5.1.3.5.15(1)

5.1.3.6.8 / 5.1.9.2.4(9) / 5.1.9.5.2 / 5.1.9.5.4(4) (Termination point located in vacuum control panel) MAIN LINE VACUUM LOW 5.1.9.2.4(8) (Terminal point from main line vacuum switch)

WASTE ANESTHETIC GAS VACUUM PUMPS

Also, For Reciprocating (Piston type) Compressors HIGH TEMPERATURE 5.1.3.5.14.3 / 5.1.9.5.4(9) / 5.1.3.5.14.4(1) (Termination point located in compressor control panel)

(Termination point located in vacuum control panel) MAINLINE EVACUATION LOW


Also, For Liquid Ring Compressors:

5.1.9.5.2 / 5.1.3.7.4.1 / 5.1.9.2.4(9) / 5.1.9.5.4(5)

5.1.9.2.4(8)

(Termination point from main line vacuum switch)

MANIFOLDS WITH RESERVE


RECEIVER FLOODED (see note #1) 5.1.3.5.14.1 / 5.1.9.5.4(7)


SUGGESTED ALARM FUNCTIONS FOR:

(Termination point from CO monitor)

RECEIVER FLOODED 5.1.3.5.14.1 / 5.1.9.5.4(7) (Termination point located in compressor control panel) HIGH WATER SEPARATOR 5.1.3.5.14.2 / 5.1.9.5.4(8) (Termination point located in compressor control panel)

CYLINDER BANK CHANGEOVER 5.1.9.2.4(1) / 5.1.3.4.12.9(1)

SUGGESTED ALARM FUNCTIONS FOR: MANIFOLDS WITHOUT RESERVE CYLINDER BANK CHANGEOVER 5.1.9.2.4(1) / 5.1.3.4.10.6 (Termination point located in power supply) MAINLINE PRESSURE HIGH 5.1.9.2.4(7) (Termination point from mainline pressure switch) MAINLINE PRESSURE LOW 5.1.9.2.4(7) (Termination point from mainline pressure switch)

(Termination point located in power supply) RESERVE IN USE 5.1.9.2.4(3) / 5.1.3.4.15.5 / 5.1.3.4.12.9(3) (Terminal point from actuating pressure switch 261920*) RESERVE LOW 5.1.3.4.12.9(4) / 5.1.9.2.4(5) (Terminal point from actuating pressure switch 261921*) MAINLINE PRESSURE HIGH 5.1.9.2.4(7) (Termination point from mainline pressure switch) MAINLINE PRESSURE LOW 5.1.9.2.4(7) (Termination point from mainline pressure switch)

Vacuum/Compressor Alarm Termination Points Located inside System Control Panel (Lower Left hand Corner)

LA

Lag Vacuum/Compressor Alarm

RF

Receiver Flooded Alarm

NOTES: 1.

Liquid air compressor and reciprocating air compressors with water cooled heads and/or water cooled aftercoolers.

2.

Mainline pressure switches for oxygen, nitrous oxide, medical air and carbon dioxide will provide both “High” and “Low” pressure alarm functions. A similar switch is provided for medical/surgical vacuum and/or waste anesthetic gas evacuation, but only a “Low Vacuum” function is required. Nitrogen requires two separate switches, one for “High” and one for “Low”

3.

Per NFPA 99, 2002 (5.1.8.2.3.) “All pressure switches, pressure gauges and pressure sensing devices downstream of the source valve shall be provided with a gas specific demand check fitting to facilitate servicing, testing or replacement.”

4.

Cable requirement for area alarm module to remote sensors; master alarm to source equipment. 18-22 gauge shielded, twisted pair Multi-conductor twisted pair cable cab be used when connecting multiple sensors.

High Temperature Alarm HT1 Compressor 1 HT2 Compressor 2 HT3 Compressor 3 HT4 Compressor 4 High Water Separator Alarm HW1 Compressor 1 HW2 Compressor 2 HW3 Compressor 3 HW4 Compressor 4

Mainline Pressure/Vacuum witch Connections Mainline Pressure Switch High, Oxygen (O2), Medical Air (AIR), Nitrous Oxide (N2O), Carbon Dioxide (CO2) Orange Wire – NC Brown Wire – Common Mainline Pressure Switch/Low Oxygen (O2), Medical Air (Air), Nitrous Oxide (N2O), Carbon Dioxide (CO2) Red Wire – NC Purple Wire – Common Mainline Vacuum Switch/Low Blue Wire – NC Purple Wire – Common Mainline Pressure Switch High, Nitrogen (N2) N.C. – NC C. – Common Mainline Pressure Switch Low, Nitrogen (N2) N.C. – NC C. – Common All Gases from High Pressure Manifold Reserve in Use/Cylinder Changover Terminal #6 – NC To Alarm Ground Terminal #7 – Common Dew Point/CO Monitor Yellow Relay, DewPoint – C & NC Red Relays, CO – C & NC

SUGGESTED ALARM FUNCTIONS FOR BULK OXYGEN SYSTEM

CRYOGENIC BULK GAS UNITS WITH CRYOGENIC RESERVE LIQUID LEVEL LOW 5.1.9.2.4(2) / 5.1.3.4.13.6(1) RESERVE IN USE 5.1.9.2.4(3) / 5.1.3.4.13.6(2) MAIN LINE PRESSURE HIGH 5.1.9.2.4(7) MAIN LINE PRESSURE LOW 5.1.9.2.4(7) RESERVE LOW 5.1.9.2.4(5) / 5.1.3.4.11.6(3) CHANGEOVER 5.1.9.2.4(1) / 5.1.3.4.13.6(5) RESERVE PRESSURE LOW 5.1.9.2.4(6) / 5.1.3.4.11.6(4) (Not Functional)

CRYOGENIC BULK GAS UNITS WITH CYLINDER RESERVE LIQUID LEVEL LOW 5.1.3.4.13.6(1) / 5.1.9.2.4(2) RESERVE IN USE 5.1.9.2.4(3) / 5.1.3.4.13.6(2) / 5.1.3.4.13.5 MAIN LINE PRESSURE HIGH 5.1.9.2.4(7) MAIN LINE PRESSURE LOW 5.1.9.2.4(7) CHANGEOVER 5.1.9.2.4(1) / 5.1.3.4.13.6(5)

HOSP ITA L PIP ING SYSTE M ARE A CONNECTION BY INS TALLER

GAS SPECIFIC DEMA ND CHECK DISS MALE THREAD 1 1/4" NPT MALE TO 1/8" NP T FE MALE RE DUCING BUSHING

1 FOR SWITCH 1/4" NP T CLOS E NIPP LE (2)

1

FOR GAUGE 1 1/4" NPT MALE TO 1/8" NP T FE MALE RE DUCING BUSHING

GAUGE 1

S UP PLIE D BY OTHERS

Mainline Pressure Switches


HOSPITAL PIPING SYSTEM AREA CONNECTION BY INSTALLER

GAS SPECIFIC DEMAND C HECK D ISS MALE THREAD 1 FOR SWITCH 1/4 " NPT CLOSE NIPPLE

1 1/4" NPT MALE TO 1/8" NPT FEMALE REDUCIN G BU SHING 1

GAUGE

Mainline Pressure/Vacuum Switch

1

1 FOR GAUGE 1/4" NPT MALE TO 1/8" NPT FEMALE REDUCIN G BU SHING

SUPPLIED BY OTHERS

Typical Oxygen (O2), Medical Air (Air), Nitrous Oxide (N2O), Carbon Dioxide (CO2) and Vacuum Installation

Ohio Medical Corporation - 1111 Lakeside Drive, Gurnee, Il 60031-4099 800-448-0770 / 847-855-0500 - Fax: 847-855-6300 - www.ohiomedical.com

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MEDICAL GAS EQUIPMENT MOUNTING HEIGHT DETAIL

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www.ohiomedical.com



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technical support Manifold Sizing Medical Air Manifold: Cylinders per Bank

400 ft3

=

X

No. of beds X

y

12

y

52

y

234

2

[Cubic ft of gas used

[Months

[# of weeks

[Cubic ft per

[Cylinders

per month per bed]

per year]

per year]

cylinder]

per bank]

Surgery Center Oxygen Cylinder Manifold: Where usage is not known Cylinders per Bank

400 ft3

=

X No. of Beds

X

y

12

y

52

y

244

2


[Months

[# of weeks

[Cubic ft per

[Cylinders

per month per bed]

per year]

per year]

cylinder]

per bank]

Hospital Oxygen Cylinder Manifold: Where usage is not known Cylinders per Bank

700 ft3

=

x No. of Beds x

12

y

52

y

244

y

2


[Months

[# of weeks

[Cubic ft per

[Cylinders

per month per bed]

per year]

per year]

cylinder]

per bank]

*With a monthly demand of 30,000 ft, bulk O2 should be used. Where usage is known: Usage, Ft3 per Month 5850 9750 13650 17600 21500 25350 29250

Duplex Manifold Size Divide by 2 for each Bank 6 10 14 18 22 26 30

N2O Cylinder Manifold:

N2 Cylinder Manifold:

CO2 Cylinder Manifold:

Divide total by 2 for each Bank

Divide total by 2 for each bank

Divide total by 2 for each bank

No. of Operating Rooms 1 to 4 5 to 8 9 to 12 13 to 16 17 to 20

No. of Operating Rooms 1 to 2 3 to 4 5 to 6 7 to 8 9 to 10 11 to 12 13 to 14

No. of Operating Rooms 1 to 8 9 to 16 17 to 32

Total No. of Cylinders 4 8 12 16 20

Total No. of Cylinders 4 8 12 16 20 24 28

Total No. of Cylinders 4 8 12

TRUSTED BRANDS OF OHIO MEDICAL™

Division of Ohio Medical



Ohio Medical Corporation 1111 Lakeside Drive - Gurnee, IL 60031-4099 USA TollFree: 800-448-0770- Fax: 847-855-6200 www.ohiomedical.com

technical support Medical Gas Cylinder Data

Gas

Oxygen (O2)

Nitrous Oxide (N2O)

Medical Breathing Air (Air)

Nitrogen (N2)

Carbon Dioxide (CO2)

Helium (He)

Cyl. Size B D E M M G H J B D E M G H J D E M M G H J D E M M G H J B D E M G H J D E M M G H J

Cylinder Dimensions

Cyl. Pressure (psig)

3-3/16" x 13" 4-3/16" x 16-3/4" 4-3/16" x 26-1/2" 7" x 43" 7" x 43" 9" x 51" 9" x 51" 9-1/4" x 55" 3-3/16" x 13" 4-3/16" x 16-3/4" 4-3/16" x 26-1/2" 7" x 43" 9" x 51" 9" x 51" 9-1/4" x 55" 4-3/16" x 16-3/4" 4-3/16" x 26-1/2" 7" x 43" 7" x 43" 9" x 51" 9" x 51" 9-1/4" x 55" 4-3/16" x 16-3/4" 4-3/16" x 26-1/2" 7" x 43" 7" x 43" 9" x 51" 9" x 51" 9-1/4" x 55" 3-3/16" x 13" 4-3/16" x 16-3/4" 4-3/16" x 26-1/2" 7" x 43" 9" x 51" 9" x 51" 9-1/4" x 55" 4-3/16" x 16-3/4" 4-3/16" x 26-1/2" 7" x 43" 7" x 43" 9" x 51" 9" x 51" 9-1/4" x 55"

2015 2015 2015 2217 2492 2217 2492 2640 745 @ 70°F 745 @ 70°F 745 @ 70°F 745 @ 70°F 745 @ 70°F 745 @ 70°F 745 @ 70°F 2015 2015 2217 2492 2217 2492 2640 2015 2015 2217 2492 2217 2492 2640 838 @ 70°F 838 @ 70°F 838 @ 70°F 838 @ 70°F 838 @ 70°F 838 @ 70°F 838 @ 70°F 2015 2015 2217 2492 2217 2492 2640

Standard Volume (14.7 psia, 70 F) Gal. 55 112 186 935 1055 1878 2110 2521 98 248 420 2155 3726 4242 4900 105 175 875 973 1743 1945 2319 103 172 860 958 1721 1908 2274 98 248 420 2155 3726 4249 4908 98 165 823 913 1638 1825 2177

Ft.3 7.4 15 24.9 125 141 251 282 337 13.1 33.2 56.1 288 498 567 655 14 12.4 117 130 233 260 310 13.7 23 115 128 230 255 304 13.1 33.2 56.1 288 498 568 656 13.2 22 110 122 219 244 291

Liters 210 424 704 3540 3993 7108 7986 9543 370 940 1590 8156 14103 16057 18550 398 662 3313 3682 6599 7363 8778 391 651 3257 3625 6514 7222 8609 370 940 1590 8156 14103 16086 18578 374 623 3115 3455 6202 6910 8241

Approx. Wt. Gas (lb-oz) 0-9.8 1-3.9 2-1.0 10-6.2 11-11.5 20-13.8 23-7.8 27.14.5 1-7.8 3-12.8 6-6.8 32-15.5 57-0.0 64-14.6 74-15.7 1-0.8 1-12.0 8-12.2 9-11.8 17-7.2 19-7.6 23-3.5 1-0.0 1-10.7 8-5.4 9-4.5 16-10.8 18-7.8 22-0.5 1-8.0 3-12.6 6-6.7 33-0.0 56-15.8 64-15.8 75-1.1 0-2.2 0-3.6 1-2.1 1-4.1 2-4.1 2-8.2 3-0.0

CGA Connection 870 Pin-Indexed

540

910 Pin-Indexed

326

950 Pin-Indexed

346

960 Pin-Indexed

580

940 Pin-Indexed

320

930 Pin-Indexed

580

TRUSTED BRANDS OF OHIO MEDICAL™




Ohio Medical Corporation 1111 Lakeside Drive - Gurnee, IL 60031-4099 USA TollFree: 800-448-0770- Fax: 847-855-6200 www.ohiomedical.com

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CONVERSION CHART ACFM / SCFM Vacuum Level (Gauge

Conversion Factor

Vacuum Level (Gauge

Conversion Factor

Vacuum Level (Gauge

Conversion Factor

1"

1.03

11"

1.58

21"

3.33

2"

1.07

12"

1.67

22"

3.75

3"

1.11

13"

1.79

23"

4.28

4"

1.15

14"

1.88

24"

5.00

5"

1.20-

15"

2.00

25"

6.00

6"

1.25

16"

2.14

26"

7.63

7":

1.30

17"

2.31

27"

10.00

9"

1.36

18"

2.50

28"

15.00

9"

1.43

19"

2.73

29"

30.00

10"

1.50

20"

3.00

TO FIND ACFM - Multiply SCFM by conversion factor EXAMPLE:

99 SCFM @ 19” Hg 99 x 2.73 = 270.27 ACFM

99 SCFM @ 25” Hg 99 x 6 = 594 ACFM

TO FIND SCFM - Divide ACFM by conversion factor EXAMPLE:

270.27 ACFM @ 19” Hg 270.276 divide by 2.73 = 99

TM

www.ohiomedical.com

594 ACFM @ 25” Hg 594 divide by 6 = 99

1111 Lakeside Drive, Gurnee, IL 60031-4099 Phone: 800-448-0770 - Fax: 847-855-6300 P/N 255277 (Rev.2) 07/2006


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1) Start at the column with the units that you wish to convert from. 2) Follow down the chart to where you find the “1”. 3) Horizontally move from that column to the column with the units that you wish to convert to.

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FLOW CONVERSION CHART GPM L/Hr m 3/Hr m 3/min

L/min

1

7.481

1.69907

0.0283

1699.07

28.318

0.134

1

0.227

0.00379

227.1

3.785

0.589

4.403

1

0.0167

1000

16.67

35.31

264.2

60

1

60000

1000

0.000589

0.0044

0.001

1.67E-05

1

0.0167

0.0353

0.264

0.06

0.001

60

1

CFM

TO USE THESE CHARTS

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VOLUME CONVERSION CHART Gal L M3 Ft In3 1 1728 7.48 0.0283 28.32 0.000579 1 0.00433 1.64E-05 0.0164 0.134 231 1 0.00378 3.786 35.34 61060 264.3 1 1000 0.0353 61.02 0.264 0.001 1 3

4) Multiply the number found in the box by the number that you have to get the converted value. or use the appropriate formula contained in the box.

TEMPERATURE CONVERSION CHART K R C 1 K x 1.8 K - 273.15 R x 0.5556 1 (R - 491.67) x 0.5556 C + 237.15 (C x 1.8) + 491.67 1 (F + 459.67) x 0.5556 F + 459.67 (F - 32) x 0.5556

#/Hr to ACFM: ACFM to #Hr:

F (K - 255.37) x 1.8 R - 459.67 (C x 1.8) + 32 1

MISCELLANEOUS CONVERSIONS #/Hr(1/60)(379/MW)(760/P)(460+T/250) ACFM(60/1)(MW/379)(P/760)(520/460+T)

NOTE: Where MW is the molecular w eight, P is the operating pressure in TORR, and T is the operating temperature in oF.

In Hg

Torr (mmHg)

mBar

In H2O

1 0.0394 0.0295 0.0735 0.883 0.0029 2.9 2.04 0.000295 0.295 29 29.921

25.4 1 0.75 1.868 22.42 0.0736 73.55 51.71 0.0075 7.5 735.7 760

33.86 1.333 1 2.49 29.89 0.0981 98.06 68.95 0.01 10 980.9 1013.25

13.6 0.535 0.402 1 12 0.0394 39.38 27.69 0.00402 4.016 393.9 406.9

PRESSURE CONVERSION CHART Ft m mm H2O PSI H2O H2O 1.133 0.0446 0.0335 0.0833 1 0.00328 3.281 2.307 0.000335 0.335 32.82 33.9

345.3 13.6 10.2 25.39 304.8 1 1000 703.1 0.102 102 10003 10333

0.345 0.0136 0.0102 0.0254 0.305 0.001 1 0.703 0.000102 0.102 10 10.333

0.491 0.0193 0.0145 0.0361 0.434 0.00142 1.422 1 0.000145 0.145 14.23 14.696

Pa

kPa

3386 133.3 100 249 2989 9.806 9806 6895 1 1000 98088 101325

3.386 0.133 0.1 0.249 2.989 0.00981 9.806 6.895 0.001 1 98.09 101.325

Kg/cm2 0.0345 0.00136 0.00102 0.00254 0.0305 0.0001 0.1 0.0703 0.0000102 0.0102 1 1.033

ATM 0.0334 0.00132 0.000987 0.00246 0.0295 0.0000968 0.0968 0.068 0.0000099 0.00987 0.968 1

NOTE: All pressure terms are absolute, not gauge.

TM

www.ohiomedical.com

1111 Lakeside Drive, Gurnee, IL 60031-4099 Phone: 800-448-0770 - Fax: 847-855-6300 P/N 255033 (Rev.3) 07/2006


Altitude Compensation for Vacuum Normal Barometric Multiplier Used for Altitude in Feet Pressure Required SCFM Sea Level 29.92"Hg (760 mmHg) 1 500 29.39"Hg (747 mmHg) 1.02 1000 28.86"Hg (733 mmHg) 1.04 1500 28.33"Hg (720 mmHg) 1.06 2000 27.82"Hg (707 mmHg) 1.08 2500 27.32"Hg (694 mmHg) 1.1 3000 26.82"Hg (681 mmHg) 1.12 3500 26.33"Hg (669 mmHg) 1.14 4000 25.84" Hg(656)mm Hg) 1.16 5000 24.90"Hg (633 mmHg) 1.2 6000 23.98"Hg (609 mmHg) 1.25 8000 22.23"Hg (565 mmHg) 1.35 9000 21.93"Hg (543 mmHg) 1.4 10000 20.58"Hg (523 mmHg) 1.45

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Receiver Sizing Formula In vacuum thermoforming it is customary to generate deep vacuum in a short period of time. A vacuum receiver is usually employed to produce this quick initial pulldown. If the installation is new, the following formula may be used to determine the size of the appropriate vacuum receiver. V2 = V1(P3-P1)/P2-P3 Where:

Equ. 1.1

V2 = Applicable vacuum receiver size [Ft3] V1 = Total mold volume (forming volume + box volume) [Ft3] P1 = Initial pressure in the mold [PSIA] P2 = Pressure in vacuum system [PSIA] P3 = Pressure in combined system [PSIA]

Example:

A vacuum receiver needs to be sized for a new installation. The forming volume is 0.8 Ft3, and the box volume is 1.2 Ft3. The initial pressure in the mold is 29.75” Hg (barometric pressure). The required pressure to form the sheet in the mold is 22” Hg. The pressure produced by the vacuum pump will be considered to be a maximum of 28” Hg.

First one must determine what are the appropriate variables, and then covert them to the appropriate units. V2 – To be determined V1 – 2 Ft3 (0.8 Ft3 + 1.2 Ft3) P1 – 14.61 PSIA (29.76” Hg(A) converted to PSIA) P2 – 0.98 PSIA (28” Hg(G) first converted to 2” Hg(A), then converted to PSIA) P3 – 3.93 PSIA (22” Hg(G) first converted to 8” Hg(A), then converted to PSIA) V2 = 2 (3.93 – 14.61)/(0.98-3.93) V2 = 7.24 Ft3 or times 7.48 gal/1 Ft3; V2= 54 gal In this case, a 60 gal receiver would be appropriate.

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1111 Lakeside Drive, Gurnee, IL 60031-4099 Phone: 800-448-0770 - Fax: 847-855-6300 1 of 6


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Another formula is useful where an existing tank is to be used. If the receiver size is known, one will wish to calculate the pressure in the combined system. P3 = (P1V1+P2V2)/(V1+V2) Equ. 1.2 Where:

V2 = Existing vacuum receiver size [Ft3] V1 = Total mold volume (forming volume + box volume) [Ft3] P1 = Initial pressure in the mold [PSIA] P2 = Pressure in vacuum system [PSIA] P3 = Pressure in combined system [PSIA]

Example:

Say that a 60 gal receiver is available from stock, what will be the final pressure in the combined system?

First one must determine what are the appropriate variables, and then convert them to the appropriate units. V2 – 8.02 Ft3 (60 gal * 1 Ft3/7.48 gal) V1 – 2 Ft3 (0.8 Ft3 + 1.2 Ft3) P1 – 14.61 PSIA (29.75” Hg(G) converted to PSIA) P2 – 0.98 PSIA (28” Hg(G) first converted to 2” Hg(A), then converted to PSIA) P3 – to be determined P3 = (14.61 * 2 + 0.98 * 8.02)/(2 + 8.02) P3 = 3.7 PSIA or converted to “Hg(G) (29.92” Hg(A)-3.7 PSIA (29.92” Hg(A)/14.7 PSIA)) P3 = 22.4” Hg(G) In most cases the system volume is equivalent to the tank volume. Generally if the pipework associated with the system is greater than 10% of the tank volume, that the volume of the pipework should be taken into account. These formulas also do not account for the collapse of the plastic in the mold. In most cases, the forming volume is so much smaller than the system volume that it does not add much to the calculations. These formulas also do not account for leaks in the system.


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Pump Sizing Formula After the vacuum receiver has produced the initial quick pulldown, the vacuum pump can be used to generate the final deep vacuum. The following formula is the general pump down formula. t = V * LN (PI/PF)/QAVG Equ. 1.3 Where:

t – Time to evacuate volume [min]

LN – Natural Log V – Total volume to be evacuated [Ft3] P1 – Initial pressure (PSIA) PF – Final pressure (PSIA) QAVG – Average volumetric flowrate of the pump (ACFM)

Note that this formula does not account for leaks in the system Example:

The 60 gal receiver from the previous example has been installed. The process requires that the vacuum pump should pull the combined system from 22.4” Hg to 28” Hg in approximately 10 seconds to increase the detail on the molded plastic. Will the S3 be able to accomplish this?

Once again the appropriate variables need to be determined. t = To be determined V – 9.22 Ft3 (1.2 Ft3 = 8.02 Ft3) {note that the forming volume is approximately 0} P1 – 3.7 PSIA (22.4” Hg(G) determined by equation 1.2) PF – 0.98 PSIA (28” Hg(G) first converted to 2” Hg(A), then converted to PSIA) QAVG – 37 ACFM The average flowrate is determined by adding the flows at different vacuum levels. The average capacity of the pump should be taken between the starting vacuum level and the ending vacuum level. For this example, the values are for the S3. 5” Hg 19” Hg 22” Hg 25” Hg 28” Hg 29” Hg

55 ACFM 44 ACFM 43 ACFM 35.9 ACFM 31 ACFM 21 ACFM

43 + 38 + 31 3 = 37.33 or 37 Avg. ACFM

Solving for time: t = 9.22 * LN (3.8/0.98)/37 t = 0.331 min or times 60 s/1 min; t = 20 s


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Basically the S3 will take 10 seconds too long to accomplish this pulldown. Try the S5 using the same parameters. All of the values remain the same, except for the average flowrate of the pump For the S5 from 22” Hg to 28” Hg: QAVG = 82 ACFM Once again solving for time: t = 9.22 * :N (3.8/0/98)/82 t = 0.149 min or times 60 s/1 min; t=9s In answer to the question that was posed in the example, the S3 will not be able to satisfy the requirement, but the S5 does satisfy the requirement. Another way to work this problem is to determine what flowrate is required given a specific time period. Example:

The 60 gal receiver from the previous example has been installed. The process requires that the vacuum pump should pull the combined system from 22.4” Hg to 28 Hg in approximately 10 seconds to increase the detail on the molded plastic. Will the S3 be able to accomplish this?

Change the formula to the following format: QAVG = V * LN (PI/PF)/t

Equ. 1.4

From the values that been used in the previous pump down examples: QAVG = 9.22 * LN (3.7/0.98)/0.1667 {t = 10 s * (1 min/60 s) = 0.1667 min} QAVG = 73 ACFM From what has been shown here, knowing the average volumetric flowrates, is that the SC10TR will be the best choice.


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S

U

P

P

O

R

Converting from SCFM to ACFM is as follows: V2 = V1(P1/P2)(T2/T1) Where:V2 – ACFM V1 – SCFM

Equ. 1.5 P1 – Absolute Pressure @ STP P2 – Absolute Pressure @ Vacuum Condition T1 – Absolute Temperature @ STP T2 – Absolute Temperature @ Vacuum Condition MW – Average Molecular Weight STP (Standard Temperature and Pressure) is 520oR and 760 mmHg(A)

An easy way to remember is: V that you want = V that you have x (P that you have / P that you want) x (T that you want / T that you have) Converting from a mass flowrate to a volumetric flowrate is as follows: V = m (1/60)(379/MW)(P1/P2)(T2/T1) Where:V – ACFM m - #/Hr

Equ. 1.6

P1 – Absolute Pressure @ STP P2 – Absolute Pressure @ Vacuum Condition T1 – Absolute Temperature @ STP T2 – Absolute Temperature @ Vacuum Condition MW – Average Molecular Weight STP (Standard Temperature and Pressure) is 520oR and 760 mmHg(A)

Example: Convert 20#/Hr of air to volumetric flowrate 25” Hg and 100oF. V = m (1/60)(379/MW)(P1/P2)(T2/T1) m = 20#/Hr P1 = 760 mmHg(A) = 29.92” Hg(A) P2 = 25” Hg(G) = 125 mmHg(A), or 4.92” Hg(A) T1 = 460 + 60oF = 520oR T2 = 460 + 100oF = 560oR V = 20 (1/60)(379/29)(760/125)(560/520), or V = 20 (1/60)(379/29)(29.92/4.92)(560/520) V = 29 ACFM @ 25” Hg and 100oF (Volumetric flowrates should be described at a specific pressure and temperature Ohio Medical Corporation - 1111 Lakeside Drive, Gurnee, IL 60031-4099 - Phone: 800-448-0770 - Fax: 847-855-6300 5 of 6

T

T

E

C

H

N

I

C

A

L

S

U

P

P

O

R

T

Converting from a volumetric flowrate to a mass flowrate is as follows: M = V (60/1)(MW/379)(P2/P1)(T1/T2), using the same symbols as above.

Equ. 1.7

Example: Convert 300 ACFM of air @ 28.5 Hg and 60oF to a mass flowrate. m = V (60/1)(MW/379)(P2/P1)(T1/T2) V = 300 ACFM P1 = 760 mm Hg = 29.92” Hg P2 = 28.5” Hg = 36 mmHg, or 1.42” Hg(A) T1 = 460 + 60oF = 520oR T2 = 460 + 100oF = 520oF, note that since T1 = T2, the division is 1, and it may be neglected m = 300 (60/1)(29/379)(36/760), or m = 300 (60/1)(29/379)(1.42/29.92) m = 65#/Hr Note that all calculations involving pressure and temperature should be performed at absolute conditions.


Affects of Altitude on Vacuum Systems Series of Technical White Papers from Ohio Medical Corporation

Ohio Medical Corporation. • 1111 Lakeside Drive • Gurnee, IL 60031 Phone: (800) 448-0770 • Fax: (847) 855-6304 • [email protected] • www.ohiomedical.com 560809 Rev. 1

TERMINOLOGY ACFM – Actual Cubic Feet per Minute CFM – Cubic Feet per Minute MDCFD – Thousand Standard Cubic Feet per Day psia – Pounds Per Square Inch in Absolute pressure SCFM – Standard Cubic Feet per Minute

Ohio Medical Corporation

1

INTRODUCTION This paper discusses the affect of atmospheric variation on a vacuum pump’s performance. To simplify the understanding, vacuum pumps are compressors operating in reverse, where inlet pressure is below the atmospheric pressure, and compressed to the discharge at atmospheric pressure. The operating range of a vacuum pump will be between atmospheric pressure down to absolute zero (a perfect vacuum). Realistically, we can not achieve a perfect vacuum (29.9 in-Hg), and the vacuum pumps used for medical and industrial applications require approximately 95% (28.5 in-Hg) of the atmospheric pressure to be evacuated in a tank. Cryogenic applications require nearly a perfect vacuum, and will achieve more than 99.9% (greater than 29.8 in-Hg) of the atmospheric pressure to be evacuated from a chamber. This paper supplements the Squire-Cogswell white paper titled: ACFM vs. SCFM vs. ICFM published in 2004 and explains the differences in compressor performance with respect to the varying atmospheric conditions. The paper also addresses appropriate “CFM” terminology that should be use in comparing compressors (SCFM) and sizing them properly (ACFM) for the off “Standard” conditions for the altitude and conditions for the area. Due to the atmospheric variation in air pressure, temperature and density – the fluid properties are constantly changing (i.e. - conditions are dependent on location, time of the year, altitude, etc.) Thus, it is important to understand that the conditions in Los Angeles vary significantly from the conditions in Denver, and a vacuum pump’s performance (capacity and operation) will vary significantly. The intent of this paper is to provide a better understanding of how vacuum pump’s capacity varies with respect to altitude, so we can properly select and size vacuum pumps for their specified and intended applications.


2

DESCRIPTION The term cubic feet per minute (CFM) describes the fluid flow rate, (measured in volume - ft3) not the weight per minute on the inlet side of a compressor. The vacuum pump’s performance capability is measured in how many one ft3 cubes of fluid are able to move per minute through the system. 1 ft

1 ft

1 ft

Figure 1 – One Cubic Feet of Volume Now consider the conditions in Los Angeles, where one cubic foot of air weighs 0.075 lbs., and in Denver, where one cubic foot of air weighs 0.062 lbs. Even though the volume is the same, the weight (mass) of the air is different. 1 ft

1 ft

Denver

Los Angeles 1 ft

1 ft

W=0.075 lbs.

1 ft

W=0.062 lbs.

1 ft

Figure 2 – Constant Volume Condition Now consider a constant weight (mass) condition. A balloon filled with 31 actual cubic feet of air in Los Angeles is then taken up to Denver. The balloon now contains 38 standard cubic feet of air.

Los Angeles

Denver

V=31 ft3

V=38 ft3

Figure 3 – Constant Mass Ohio Medical Corporation

3

The two examples illustrate the confusion of measuring volume due to the fact air is compressible. In this instance, the number of gas molecules occupying a particular volume, depends primarily on the pressure and temperature conditions of that location. At a microscopic level, the air molecules are closer together (greater air density) in Los Angeles compared to the air molecules in Denver.

Denver

Los Angeles

Figure 4 – Variation in Air Molecule Density A variation in air pressure results in a variation in air density, as show in Figure 4, and is consistent with constant volume concept in Figure 2. Another way to look at this is to analyze the number of air molecules in a 120-gallon receiver tank at atmospheric pressure at Los Angels and at Denver, where the former (higher pressure) tank occupies a greater number of molecules. The weight and density vary primarily because the atmospheric pressure is significantly different between the two cities, as show in Table 1. Note the terms for “actual” and “standard” for the volumes described above leads us to “SCFM” and “ACFM”. City Los Angeles Denver

Altitude (ft) 0 5280

Atmospheric Pressure (psia) 14.69 12.12

Atmospheric Pressure (in-Hg) 29.92 24.68

Table 1 – Variation in Atmospheric Pressure between the Two Cities

THE “GENERAL RULE” To simplify the understanding of the affect of vacuum pumps with respect to variation in altitude, the following illustration simplifies and points out the concept to understand prior to proceeding with a more theoretical view point on the matter. For this paper, we will assume only the attitude is varying, while keeping other conditions constant (like temperature, humidity, etc,).


4

The first general rule is to understand that the maximum vacuum level that can be achieved is with respect to the atmospheric conditions in the area. For example, assume the maximum vacuum that can be achieved theoretically in Los Angeles (sea level) is 29.92 in-Hg, but in Denver (5280 feet above sea level) is 24.68 in-Hg. City Los Angeles Denver


Atmospheric Pressure (in-Hg) 29.92 24.68

Atmospheric Pressure (in-Hg using the rule) 29.92 24.64

Table 2 – “Rule of Thumb” for Atmospheric Pressure As a general “Rule of Thumb”, for every 1000 feet above sea level, the maximum possible vacuum is reduced by approximately one in-Hg (0.491 psi). By using this rule one can quickly determine the maximum possible vacuum for the area. Note the accuracy of this “Rule”, as there is only a 0.16% difference between the approximated and the actual pressure (shown in Table 2). PERFORMANCE BASED ON CAPABILITY Next consider that a vacuum system’s performance is a percentage of the atmospheric pressure that it can exhaust from a closed system. At sea level, Los Angeles has a barometric pressure at 29.92 in-Hg. Thus, a vacuum pump with a maximum capability of 24.00 in-Hg will have are rating of 80.2%. 24.00 psi = 0.802 29.92 psi

Then, the 80.2% rating can be assigned to the vacuum pump to determine its capability in Denver. 0.802 × 24.68 = 19.79 in − Hg

The 80.2% rating applied to the maximum possible vacuum (24.68 in-Hg) results in a maximum vacuum of 19.79 in-Hg for this pump in Denver. This is a very important point to understand and consider for vacuum performance and sizing for your location. If the user needs a vacuum that can achieve 22 in-Hg in Denver, a pump with at least a 89% vacuum capability is needed, or a pump that will achieve at least 26.7 in-Hg capability in Los Angeles.


5

PERFORMANCE BASED ON CAPACITY

% CAPABILITY

In a closed system vacuum pumps use kinetic energy to move air through a closed system. At low vacuum levels large volumes of air can be evacuated through the system, but at higher vacuum levels, the capacity decreases, due to increased leakage from a larger pressure differential with the environment and there is additional resistance to flow. This phenomena is illustrated in Figure 5.

0

5

10

15

20

25

VACUUM (in-Hg) Figure 5 – Vacuum Capacity for Los Angels and Denver


6

SUMMARY This paper summarized the affect of atmospheric variation on a vacuum pump’s maximum performance. By comparing conditions in Los Angeles from the conditions in Denver (capacity and operation) and using the general “Rule of Thumb” (for every 1000 feet above sea level, the maximum possible vacuum is reduced by approximately one inHg), we can quickly determine the maximum possible vacuum for the area. Finally, a specifier can use the “Rule of Thumb” for sizing a vacuum system properly. In addition, the reference pressure, temperature, and required vacuum must be specified, in addition to the required capacity and capability. When specifying the vacuum requirement, the worst case conditions should be used (i.e. - generally hot days – lower air density). Other important factors to consider in vacuum system sizing are: • Vacuum requirement or demand in a given day • Normal operating conditions • Other operating conditions (hot days are the worst) • Single-stage or two-stage vacuum • Electrical characteristics and power requirement • Area classification (Elevation)


7

ACFM vs. SCFM vs. ICFM Series of Technical White Papers from Ohio Medical Corporation

Ohio Medical Corporation • 1111 Lakeside Drive • Gurnee, IL 60031 Phone: (800) 448-0770 • Fax: (847) 855-6304 • [email protected] • www.ohiomedical.com 560808 Rev. 2

TERMINOLOGY ACFM – Actual Cubic Feet per Minute CFM – Cubic Feet per Minute ICFM – Inlet Cubic Feet per Minute MDCFD – Thousand Standard Cubic Feet per Day psia – Pounds Per Square Inch in Absolute pressure SCFM – Standard Cubic Feet per Minute NOMENCLATURE P1 Barometric pressure at the non-standard site in psia T1 Ambient air temperature in °R PF Pressure after the inlet filter in psia TF Air temperature after the inlet filter in °R Psat Saturation Pressure φ Relative Humidity at the non-standard site Tstd Standard temperature in degrees in °R (60°F = 60 + 460 = 520 °R) Pstd Standard air pressure in psia (14.696 psia)

Ohio Medical Corporation.

1

INTRODUCTION The term CFM is often confusing and difficult to define for one condition, and one definition does not satisfy all conditions we encounter in our customer’s applications throughout the world. Simply put, CFM is an acronym for Cubic Feet per Minute, and defines the volumetric flow rate of a fluid displaced by a pump (like a compressor, a blower, or a booster). The term CFM is generally used to describe a pump’s capacity, and is used to determine the size of the source system for medical, industrial and other applications. The common terms used to specify a volumetric flow rate in different industries are SCFM, ACFM, ICFM, MCFM, MSCFD, etc. Often times these terms are very vague, and in turn, misunderstood. The primary reason for all the difficulties described above is because air is a compressible fluid, due to the atmospheric variation in air pressure, temperature and density - the fluid properties are constantly changing. The conditions are dependent on location, time of the year, altitude, etc. Thus, it is important to understand that the conditions in Los Angeles vary significantly from the conditions in Denver. The terms SCFM, ACFM and ICFM are often used to define the different instances and conditions of a compressor’s capacity and operation. If the CFM terms are used appropriately, they can be useful in the direct and relative comparison to their operating conditions, and to other source systems. The intent of this paper is to provide a better understanding of SCFM, ACFM and ICFM and their meaning, so we can properly select and size compressors for their specified and intended applications.


2

DESCRIPTION The term cubic feet per minute (CFM) describes the fluid flow rate, (measured in volume - ft3) not the weight per minute on the inlet side of a compressor. The compressor’s performance capability is measured in how many one ft3 cubes of fluid are able to move per minute through the inlet. 1 ft

1 ft

1 ft

Figure 1 – One Cubic Feet of Volume Now consider the conditions in Los Angeles, where one cubic feet of air weighs 0.075 lbs., and in Denver, where one cubic feet of air weighs 0.062 lbs. Even though the volume is the same, the weight (mass) of the air is different. 1 ft

1 ft

Denver

Los Angeles 1 ft

1 ft

W=0.075 lbs.

1 ft

W=0.062 lbs.

1 ft

Figure 2 – Constant Volume Condition Now consider a constant weight (mass) condition. A balloon filled with 31 actual cubic feet of air in Los Angeles is then taken up to Denver. The balloon now contains 38 standard cubic feet of air.

Los Angeles

Denver

V=31 ft3

V=38 ft3

Figure 3 – Constant Mass


3

The two examples illustrate the confusion of measuring volume due to the fact air is compressible. In this instance, the number of gas molecules occupying a particular volume, depends on the pressure and temperature conditions of that location. At a microscopic level, the air molecules are closer together (greater air density) in Los Angeles compared to the air molecules in Denver.

Denver

Los Angeles

Figure 4 – Variation in Air Molecule Density A variation in air pressure results in a variation in air density, as show in Figure 4, and is consistent with constant volume concept in Figure 2. Another way to look at this is to analyze the number of air molecules in a 120-gallon receiver tank at 80 psia and 100 psia, where the higher pressure tank occupies a greater number of molecules. The weight and density vary primarily because the atmospheric pressure is significantly different between the two cities, as show in Table 1. Note the terms for “actual” and “standard” for the volumes described above leads us to “SCFM” and “ACFM”. City Los Angeles Denver


Atmospheric Pressure (psia) 14.69 12.12

Table 1 – Variation in Atmospheric Pressure between the Two Cities SCFM and ACFM The term standard cubic feet per minute (SCFM) is usually used as a standard reference condition for flow rate performance for atmospheric pressure at sea level, as opposed to actual cubic feet per minute (ACFM) is typically used to rate flow rate performance of compressor systems for actual pressure and temperature. SCFM is defined as air at 14.696 psia and 520°R (60 °F). Sometimes other conditions are used, such as 530°R (70°F), 528°R (68°F), 0% and 36% Relative Humidity for describing the standard conditions. It is important to remember SCFM is defined by a fixed set of conditions or common reference point for comparing different compressors systems. Otherwise the consequences are the improper sizing of the compressor system for its true application. This point will be apparent in the two examples to follow.


4

The conditions at sea level are generally not experienced by our customers and for practicality purposes ACFM is typically used for sizing compressors for these applications (+100°F and lower pressures). The conversion for ACFM from SCFM is shown by the formula below. ACFM = SCFM ×

Pstd T × 1 P1 − Psat1 × φ1 Tstd

(

)

Equation 1

Note, absolute units must be used in the equation. SCFM – ACFM EXAMPLE 1 – Normal Day For this example we will reference a 30-hp compressor operating at 1020 rpm, and use it in Los Angeles and Denver to demonstrate how SCFM and ACFM should be used. Assume the requirement for compressed air is 125 psig discharge pressure, and 100 SCFM of demand, and the site ambient conditions are T1 = 80 °F (540 °R), P1 = 14.7 psia and φ = 75%, and this results in the following: ACFM = 106.6 If we assume that all ambient conditions remain the same with the exception of moving the compressor to Denver, where the atmospheric pressure will drop to P1 = 12.12 psia, the resulting volumetric flow requirement becomes: ACFM = 130.0 In order to deliver the same amount of work (100 SCFM at 125 psig), the compressor in Denver must ingest larger quantities of the lower-density air, due to the change in the atmospheric pressure. Location Los Angeles, CA Denver, CO

SCFM 100 100

ACFM 106.6 130.0

% Diff. 6.6 % 30.0 %

Table 1 – Normal Day between the Two Cities To provide the required 100 SCFM of work in Denver, the compressor must be able to process 130 ACFM. SCFM – ACFM EXAMPLE 2 – Hot Humid Day For this example we will reference the first example for Los Angeles and Denver and change the conditions to a hot humid day. Assume the same requirements and conditions except for the ambient temperature of T1 = 100 °F (560 °R) and relative humidity of φ = 100%, which results in the following:


5

Location Los Angeles, CA Denver, CO

SCFM 100 100

ACFM 115.1 141.6

% Diff. 15.1 % 41.6 %

Table 3 – Hot Humid Day between the Two Cities The results at the higher temperature and higher humidity condition show an even greater amount of air is needed (approximately 10% more air is needed compared to Example 1) to meet capacity requirements. Thus, we recommend using hot humid days to calculate the worst case conditions for sizing a system. Tables can be constructed to size systems from Equation 1, but it is up to the specifier to determine the proper conditions. Table 4 in Appendix A shows the expansion ratio conversions for SCFM and ACFM for the conditions described in this example. ICFM The term Inlet Cubic Feet per Minute (ICFM) is used by compressor vendors to establish the conditions at the inlet of compressor – in front of the inlet filter, blower, or booster. If the pressure and temperature condition at the inlet is the same as after the filter, blower, or booster, then the ICFM and ACFM values will be the same. However, as the air passes through these components, there will be always be a pressure drop or rise, and Equation 2 is used to approximate ACFM. ACFM = ICFM ×

P1 TF × PF T1

Equation 2

Then ICFM is used to measure inlet capacity, which will approximate ACFM for this type of a system. Note, when a blower or booster is added, the inlet may experience significantly higher pressure and temperature conditions than the actual ambient conditions. Greater the difference in pressure and temperature, greater the difference in ACFM and ICFM. Finally, there are losses (air seal, heat, etc.) associated with the use of these components and coupled with the pressure and temperature differences, the use of ICFM will result in a misleading outcome in determining a compressor’s capability. Note at higher altitudes, the specifier must account for the decrease in air pressure when estimating a compressor’s performance and sometimes blowers or boosters are used for economic reasons, but this is not always the best solution. Thus, in certain markets, like the Medical, where tighter controls are employed, ICFM should not be used to determine a compressor’s capacity, instead ACFM should be used.


6

CONCLUSION This paper defined, summarized and applied the terms SCFM, ACFM and ICFM, and the differences between them. The term CFM, at a fundamental level, is defined such that a compressor will pump a specific volume of air in a given amount of time when the compressor speed and flow resistance matches the test conditions. A specifier’s most difficult task is sizing a compressor properly, by specifying the compressor’s required capacity. It is important to note that the proper understanding of these terms will help a specifier in selecting a compressor. The specifier should use SCFM to compare differences in compressor capacities, and ACFM for actual nonstandard site conditions and proper load applications. ICFM should be used only when a filter, a booster or a blower is added to the system, and should not be used in determining compressor selection, due to misleading results. Finally, the reference pressure, temperature, and discharge pressure must be specified, in addition to the required capacity. When specifying the compressed air requirement, the worst case conditions should be used (i.e. - generally hot humid days, as shown in Example 2). Otherwise, there will be confusion in the sizing process. Other important factors to consider in compressor capacity and system sizing are: • Air requirement or demand in a given day • Normal operating conditions • Other operating conditions (hot humid days are the worst) • Single-stage or two-stage compressor (compression ratio) • CFM reduction due to flow resistance • Electrical characteristics and power requirement • Area classification (Elevation) • Compressors with a higher CFM rating will pump more air than compressors with lower CFM


7

APPENDIX A

Volume Expansion Ratio Pressure (psia) 14.70 14.50 14.25 14.00 13.75 13.50 13.25 13.00 12.75 12.50 12.25 12.00 11.75 11.50 11.25 11.00 10.75 10.50 10.25 10.00 9.75 9.50 9.25 9.00 8.75 8.50 8.25

SCFM to ACFM

ACFM to SCFM

1.151 1.168 1.190 1.213 1.237 1.261 1.287 1.314 1.341 1.371 1.401 1.433 1.466 1.500 1.537 1.575 1.615 1.658 1.702 1.749 1.799 1.851 1.907 1.966 2.029 2.097 2.168

0.869 0.856 0.840 0.824 0.809 0.793 0.777 0.761 0.745 0.730 0.714 0.698 0.682 0.666 0.651 0.635 0.619 0.603 0.588 0.572 0.556 0.540 0.524 0.509 0.493 0.477 0.461

Table 4 – Volume Expansion Ratio Conversion Chart


8

Pressure Drop in Air Piping Systems Series of Technical White Papers from Ohio Medical Corporation

Ohio Medical Corporation • 1111 Lakeside Drive • Gurnee, IL 60031 Phone: (800) 448-0770 • Fax: (847) 855-6304 • [email protected] • www.ohiomedical.com

560807 Rev 2

1

TERMINOLOGY ACFM – Actual Cubic Feet per Minute CFM – Cubic Feet per Minute GPM – Gallons per Minute NOMENCLATURE Constants: g – Acceleration Due to Gravity (32.2 ft./sec2) γ - Specific Weight (lb/ft3) ρ - Density of Fluid (slugs/ft3) µ - Dynamic Viscosity (lb*s/ft2) ε - Equivalent Roughness (.0005 ft. for Galvanized Pipe) KL – Loss Coefficient for Fittings (Found in Industrial Literature or College Text) Variables: zn – Height at Position “n” (ft.) V - Velocity of Fluid (ft/sec.) D - Diameter of Pipe (in. or ft.) A – Cross Sectional Area of Pipe (in.2) L – Pipe Length (ft.) hL – Head Loss (ft.) pn – Pressure at Node “n” f – Friction Factor

2

INTRODUCTION Ever since the development of piping systems throughout civilization there has been the need to analyze pipe size for optimal flow. In 1738 Daniel Bernoulli had developed an equation to represent all variables within a piping system, as shown below: p1

2

2

V p V + 1 + z1 = 2 + 2 + z 2 + ∑ hL γ 2g γ 2g

(1)

From Bernoulli’s equation, we can see how pressure, velocity and position relate to one another, and many derivations can be created from this equation. Depending on the assumptions made and under certain conditions, some of the variables become negligible and can be removed to simplify the equation, and result in a simpler solution. The nature of this paper is to solve for the pressure drop (or commonly referred to the back pressure) which is essentially the pressure difference between two points in a piping system. The pressure drop is critical when sizing pipe. A pump that is integrated within a piping system is designed such that it will withstand certain forces at the inlet and exhaust. If the pump is subjected to forces greater than the ones prescribed, there is a high potential for damage to the internal pump components, and thus the designed flow will be affected. This paper will focus on the flow of air, although it can be shown that other fluids can also be modeled using the same methodology. Like other media that flows within a piping system, air has its own characteristics which benefit and hinder the process. There are numerous ways in which to solve for the pressure drop of piping system. That is to say, one can incorporate the use of a computer with a plethora of software available. However, the underlying equations used in these programs follow the same fundamental laws of physics found in any collegiate Fluid Mechanics textbook. In addition, sound engineering judgment should be used when sizing pipe. While a cost-effective solution may look good on the bottom line, a safe and reliable system should have precedence in any design. For our discussion the following assumptions can be made: Assumptions: 1. Air Flow will be turbulent. 2. The temperature for the ambient air will be 70oF 3. Air flow will be defined using ACFM. With these assumptions we can model our system.

3

BACKGROUND: As we all have either experienced, or heard about, the phenomenon referred to as turbulence. Essentially turbulence is a random positioning of the flow of air. Whereas in a laminar condition, the flow of air is uniform and follows a smooth, organized path. For air piping, we assume that the air flow will be turbulent due to surface randomness in the piping fabrication and/or power fluctuation in the air source equipment. A visual depiction of laminar and turbulent flow is shown below: Laminar Flow

Figure 1 Turbulent Flow

Figure 2 To see if the flow of air will be turbulent or laminar, we solve for a parameter referred to as the Reynolds number. The Reynolds number is a dimensionless number which is obtained from the following equation: Re =

ρ ×V × D µ

(2)

The conditions for if the flow is turbulent or laminar is as follows: If Re < 2100 then the flow is Laminar If Re > 4000 then the flow is Turbulent If 2100 < Re < 4000 then the flow is classified as in Transition.

4

To determine if the flow rate is laminar or turbulent, the Reynolds number should be calculated. The combination of the Reynolds number, equivalent roughness and pipe diameter we can determine the friction factor from the Moody chart. (Moody charts can be found in industrial literature and in college text books.) The friction factor is used in the equations below. OTHER EQUATIONS: Some of the other equations used to determine the pressure drop are in this section. We can solve for the velocity of the flow by dividing the ACFM by the cross sectional area:

Velocity ( ft / s) =

Volumetric Flow Rate( ft 3 / s) Area( ft 2 )

(3)

Where the area is solved by: A = π ⋅r2

(4)

Once the velocity is found, we can then check to see if the flow is turbulent, or laminar, by utilizing the Reynolds equation (as mentioned previously). The pressure drop in a piping system can be broken down into two (2) equation forms: 1. Major Pressure Losses (Pipe Losses) 2. Minor Pressure Losses (Losses through fittings, valves, etc.) The Equation for Major Losses: p1 − p2 = f

l 1 ρV 2 D2

(5)

The Equation for Minor Losses:

p1 − p2 = γ ∑ hL Where hL is found by:

hL = K L

(6)

V2 2g

(7)

And the constant KL is found in tables of either college text, or industrial references. Combining Equations (6) and (7) we can solve the pressure differential directly:

p1 − p 2 = γ ∑ K L

V2 2g

(8) 5

Once the pressure drop has been calculated for the pipe length and all of the fittings/valves, the total pressure drop can be found by the summation of all components. In Equation form: (9)

pTotal = p Fittings + p Pipe + pValves

COMPRESSIBLE VERSUS INCOMPRESSIBLE:

The reader might be wondering that since air is a gas, shouldn’t the flow be characterized as compressible? The answer to this question is dependent on many conditions. Depending on the length of the pipe and the complexity of the arrangement of fittings and valves, the pressure drop may, or may not, be small relative to the initial pressure. If the pressure drop is small enough, then you can assume the fluid is incompressible. Otherwise, the flow is Compressible, and complicates the analysis. An example to find the pressure ratio is as follows: We have a pipe length of 7’-0” and the pressure drop should be no greater than 1.0 psi per 7’-0”. The pressure at the beginning is 14.7 psi.

( p1 − p2 )

(10)

p1

 1 psi   (7 ft )  7 ft  = .068 = 6.8% 14.7 psi

This ratio is small enough to assume an incompressible flow. Sound judgment and experience should be used when applying this equation. In different industries, different values are used to make the difference.

6

EXAMPLE: Given: A Squire-Cogswell S750TR-T2 system needs to have an exhaust line sized properly. The customer needs to pipe the system to the outside the building. The customer knows that there will be 100 ft. of pipe, three 90o elbows, and two 45o elbows. All Piping will be galvanized (ε = 0.0005 ft.). Air temperature is 60oF and atmospheric pressure is 14.7 psi. Find: The proper exhaust pipe diameter for this system. Known: The given flow rate is 163.8 ACFM per pump. The exhaust for the pump is 11/2”. (It is always advisable to check with the manufacturer of the pump for a back pressure allowance. Depending on the manufacturer of the pump, the allowable back pressure may vary.) The back pressure should not be greater than 1 psi. Solution:

First we solve for the major lossesFind the velocity of the fluid from the flow rate using equation (3): ft 3 1min ft 3 V = 163.8 × = 2.73 min 60 sec sec V = 2.73

ft 3 1 × sec Cross Sectional Area of Pipe

Let’s assume a 1-1/2” (0.0625 ft.) Cross Sectional Diameter: Therefore: V = 2.73

ft 3 1 ft × = 222.6 2 sec (0.0625 ft ) × 3.14 sec

The next variable we look for is the Reynolds Number using equation (2):

Re =

ρVD µ

 slugs   ft.   0.00238 3   222.6  (0.125 ft.) s  ft   Re =  = 176,471 − 7 lb ⋅ s 3.74 × 10 ft 2

7

Once the Reynolds number is found then the flow can be determined as either turbulent or laminar. In this example, the flow is turbulent. The frictional factor can be found from knowing the Reynolds number, relative roughness and diameter of the pipe. From the Moody Chart f = 0.029 Using equation (5) to solve for the major losses:  100 ft.  1  slugs  ft    0.00238  222.6 p1 − p 2 = 0.029  3  sec  ft   0.125 ft.  2  p1 − p 2 = 1368

p1 − p 2 = 1368

2

lb ft.2

lb 1 ft 2 × ft.2 144in 2

∆p = 9.49 psi

Second we solve for the minor losses (i.e. through fittings and valves) using equation (8):

p1 − p 2 = γ ∑ K L

2   ft      222.6  lb   s p1 − p 2 = 0.0765 3 3 1.5 ×  ft  ft    2  32.2 2    s    

∆p = 359

V2 2g 2   ft       222.6     s     + 2  .4 ×  ft     2  32.2 2     s     

lb ft 2

lb 1 ft 2 ∆p = 359 2 × ft 144in 2 ∆p = 2.50 psi pTotal = pFittings + pPipe

8

pTotal = 9.49 psi + 2.50 psi ∆pTotal = 11.99 psi

As we can see from this solution, the pressure drop is much higher than what should be observed in the pumps. Therefore, other iterations of the example are shown in Table 1:

Iteration

Pipe Size (in.)

Major Losses Pressure Drop in Pipe (psi)

Minor Losses Pressure Drop in Fittings (psi)

Total Pressure Drop (psi)

1

1 1/2

9.49

2.20

11.99

2

3

0.24

0.14

0.38

3

2 1/2

0.64

0.28

0.92

Table 1 EXPERIMENT:

The above theory was tested in our lab to see if the data correlated with the solutions. The experiment was set up as seen in the following pictures:

9

Pressure Measuring Device: Merical DP2000I (Accuracy 0.05%R) Pump: 45 lpm Volumetric Free Flow, 12 VDC, 4.0 Amp Pipe Size: 1/8” (.269ID) Fittings: 1/8” Tee’s (Qty. 2) 1/8” Pipe Nipples (as appropriate) 1/8” Pipe Couplings (as appropriate) Conditions for the test: Ambient conditions at Sea Level: Temperature - 70oF Pressure – 14.7 PSIA Flow Rate: 45 lpm (Approximately 1.6 ACFM) The pressure drop was measured at different pipe lengths. Refer to the data below.

Length

Major Losses Calculated (psi)

6”

0.04

12”

0.09

24”

0.17

36”

0.26

48”

0.35

Minor Losses Calculated (psi) Tee Branch Flow: 0.05(2) = 0.10 Elbow: 0.04(1) = 0.04 Tee Branch Flow: 0.05(2) = 0.10 Elbow: 0.04(1) = 0.04 1 Coupling: 0.002(1) = 0.002 Tee Branch Flow: 0.05(2) = 0.10 Elbow: 0.04(1) = 0.04 3 Couplings: 0.002(3) = 0.006 Tee Branch Flow: 0.05(2) = 0.10 Elbow: 0.04(1) = 0.04 5 Couplings: 0.002(5) = 0.010 Tee Branch Flow: 0.05(2) = 0.10 Elbow: 0.04(1) = 0.04 7 Couplings: 0.002(7) = 0.014

∆P Calculated (psi)

∆P Measured (psi)

0.18

0.19

0.23

0.23

0.32

0.30

0.41

0.37

0.49

0.42

Table 2

10

Pressure Drop Experiment 1 0.9 0.8

Pressure Drop (psi)

0.7 0.6 Calculated

0.5

Measured

0.4 0.3 0.2 0.1 0 6

12

24

36

48

Pipe Length (Inches)

Figure 3

As we can see from the data above, the calculated and measured data points correlate with each other. The average difference is 0.03 psi between the calculated and measured data points. The non-linear behavior of the measured values is attributed to the random behavior of air. From Figure 3, one can see that the pressure data separates from the 12” point. The separation of data points can be attributed to leaks or irregularities in the pipe (i.e. burrs, surface irregularities from galvanizing etc.) The leaks in the piping system will decrease the flow rate, this in turn decreases the pressure. It is also interesting to note that as the pipe length increases, so does the pressure. This is both demonstrated in the measured and calculated values.

11

CONCLUSION:

Optimization of piping is essential in today’s new construction of building systems. Due to ever increasing costs of steel and copper, there is no other alternative but to take a closer look at the piping system. In the past, a “rule of thumb” gave a large margin of safety. However, the Engineer, Contractor and Architect must understand that the margin of safety can be held while decreasing the excess size of the pipe. As long as the pressure drop is within the pump manufacturer’s specifications, the performance will not be affected. The pressure drop in the piping system directly affects the performance of the pump. Essentially the pressure drop produces additional forces that directly and indirectly affect the internal parts. It should be noted that having an excess size diameter of pipe can be detrimental as well (i.e. oversized). If the area is increased, the excess (stagnant) air will act as an obstruction to the flow and therefore create a greater turbulence. Another detrimental effect, besides damage to the internal components of the pump, is the reduction of air capacity the pump removes. The back pressure acts as an obstruction to the flow, therefore hindering capacity. The example could be solved in different ways. In fact we could have different pipe sizes in this line. That is to say, we could have calculated for a run 50’-0” of 1 ½” Dia. and 50’-0” of 3” Dia. The calculation above is good for approximating the pipe size for the entire length of the pipe, and it is also good for solving for smaller sections of pipe. In addition, this paper makes lot of assumptions regarding the condition of the air flow and the ambient conditions. It can be argued that a more detailed analysis would be appropriate, and in other cases a more general solving approach would be appropriate. As shown in the example, there are many steps that need to be followed to give us an optimized pipe size. There are many opportunities to overlook error by using these equations. Therefore, it is recommended to use sound industry judgment when solving for the pressure drop and interpreting the results.

12

1111 Lakeside Drive ♦ Gurnee, IL 60031-4099 ♦ 847-855-0500 ♦ www.ohiomedical.com

MEDICAL VACUUM AND COMPRESSED AIR SYSTEMS LIMITED WARRANTY 1. Ohio Medical Corporation warrants to the original purchaser its Medical Vacuum and Compressed Air Systems to be free from functional defects in material and workmanship for a period of twenty four (24) months from the date of shipment, or for a period of twelve (12) months from the date of start-up, whichever comes first. a. Start-up shall only be done by an authorized representative of Ohio Medical Corporation. 2. In the event there is a functional defect either in material or workmanship Ohio Medical Corporation will only repair or replace any part or component which is proven to be defective. a. System Components sold as individual items are not warranted to include job site installation and wiring, and the warranty set forth in Paragraph 1 is limited to complete units which include all factory installed components and interconnected piping and wiring. b. Labor on site is limited to functional defects in workmanship found to be defective at the time of start-up. c. The replacement of normal wearing or maintenance items (including but not limited to packings, mechanical seals, oil seals, piston rings, contacts, coils, fuses, etc.) made in connection with normal maintenance services are not covered by this warranty. 3. To obtain service within the warranty period, first contact your authorized Ohio Medical Corporation dealer or the Ohio Medical Corporation Service Department. Ohio Medical Corporation responsibility under this warranty shall be limited to providing at Ohio Medical Corporation sole discretion new or similar rebuilt replacement parts to replace any component found to be defective within the warranty period. a. Labor to repair any part or component proved to be defective within the warranty period will be provided at no charge for any item returned to our factory adequately packaged and insured with shipping costs prepaid. Standard surface freight shipping cost and return of the repaired part or component will be paid by Ohio Medical Corporation. b. Before returning any part or component to the factory, proper return authorization must first be obtained from Ohio Medical Corporation Service Department. 4. The warranty is valid only when the product has been property installed according to Ohio Medical Corporation specifications, used in a normal manner and serviced according to factory recommendations. It does not cover failure due to damage which occurs in shipment or failures which result from accidents, misuse, abuse, neglect, mishandling, alteration, misapplication or damage that may be attributable to acts of God. Similarly, this warranty does not apply to units that are re-sold or rented to others by the purchaser. 5. Ohio Medical Corpioration shall not be liable for incidental or consequential damages resulting from the use of this product. There are no expressed or implied warranties which extend beyond the warranty of fitness for a particular purpose to the equipment and/or to its parts and components. 6. THE CONDITIONS OF THE BUYER’S RESPONSIBILITY ARE: a. The equipment is stored properly before installation. b. The equipment is installed according to Ohio Medical Corporation specifications and installation procedures. c. The room where the equipment is installed meets stated operating temperatures. d. The equipment is placed into initial operation by an authorized representative of Ohio Medical Corporation. e. The equipment is properly maintained and is not repaired or altered unless by an authorized representative of Ohio Medical Corporation. 573010 (Rev.5) 503004 Producers of Ohmeda Suction and Oxygen Therapy Devices, Aeros® Instruments Portable Suction Machines and Squire-Cogswell Medical Gas Pipeline Equipment, Medical and Industrial Vacuum Systems and Air Compressor Packages

1111 Lakeside Drive ♦ Gurnee, IL 60031-4099 ♦ 847-855-0500 ♦ www.ohiomedical.com

OHIO MEDICAL CORPORATION MEDICAL GAS PIPELINE EQUIPMENT LIMITED WARRANTY 1.

OHIO MEDICAL CORPORATION warrants the Medical Gas Pipeline Equipment to be free from functional defects in material and workmanship for a period of twenty-four (24) months from the date of shipment or twelve (12) months from the date of start-up, whichever occurs first. Within said period Ohio Medical Corporation will repair or replace any part or component which is proven to be defective in either material or workmanship.

2.

To obtain service within the warranty period, first contact the Ohio Medical Service Department.

3.

Ohio Medical Corporation's responsibility under this warranty shall be limited to providing at Ohio Medical Corporation's sole discretion, new or replacement parts to replace any component found to be defective within the warranty period. Installation of user replaceable items will be the user's responsibility.

4.

Labor to repair any part or component proved to be defective within the warranty period will be provided at no charge for any item returned to our factory adequately packaged and insured with shipping costs prepaid. Standard surface freight shipping cost to return the repaired part or component to the user will be paid by Ohio Medical Corporation. a.

Before returning any part or component to the factory, proper return authorization must first be obtained from Ohio Medical Service Department.

b.

The user will be required to issue a purchase order for replacement items. Upon receipt of the defective items, Ohio Medical Corporation will issue a credit to the user in the amount equal to the purchase order.

5.

This warranty is valid only when the product has been properly installed according to Ohio Medical Corporation specifications, used in a normal manner and serviced according to factory recommendations. The warranty does not cover failures due to damage which occurs in shipment or failures which result from accidents, misuse, abuse, neglect, mishandling, alteration, misapplication or damage that may be attributable to acts of God.

6.

Ohio Medical Corporation shall not be liable for incidental or consequential damages resulting from the use of this product. There are no expressed or implied warranties which extend beyond the warranties set forth above. Ohio Medical Corporation makes no warranty of merchantability or fitness for a particular purpose to equipment and to its parts and components.

7.

THE CONDITIONS OF THE BUYER'S RESPONSIBILITY ARE: 1. 2. 3.

The equipment is stored properly before installation; The equipment is installed according to Ohio Medical Corporation's specifications and installation procedures; The equipment is properly maintained and not altered unless by an authorized representative of Ohio Medical Corporation. 573078 (REV.2) 580273

Producers of Ohmeda Suction and Oxygen Therapy Devices, Aeros® Instruments Portable Suction Machines and Squire-Cogswell Medical Gas Pipeline Equipment, Medical and Industrial Vacuum Systems and Air Compressor Packages

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