Laboratory Airflow Control Devices I2SL Denver – August, 2017

Laboratory Airflow Control Devices Agenda Standards Mechanical Operation Flow and Pressure Ranges Control Methods and Accuracies Speed of Response Maintenance Airflow Sound Material Options Coatings

Laboratory Airflow Control Devices Standards

Laboratory Airflow Control Devices Standards & Guidelines Primary Standards ANSI Z9.5 – 2012 ASHRAE 110 – 2016 ASHRAE Lab Design Guide, 2nd Ed - 2015 Related Standards ASHRAE 90.1 – 2010 NEBB Fume Hood Performance Testing

Laboratory Airflow Control Devices Mechanical Operation

Laboratory Airflow Control Devices Mechanical Operation Standard Accuracy Damper Control Valve Direct airflow measurement using in-stream flow sensors that utilize velocity pressure Typical 6:1 turndown ratios Typically require three duct diameters of straight duct leading into and out of the valve

Laboratory Airflow Control Devices Mechanical Operation High Accuracy Damper Control Valve Direct airflow measurement using velocity pressure, vortex shedding sensors, or thermal dispersion Typical 10:1 turndown ratios Typically require one duct diameters of straight duct leading into and out of the valve Damper Blade Hi and Low Pressure Ports Airflow

Laboratory Airflow Control Devices Mechanical Operation Venturi Valves Electronic flow feedback Mechanical pressure independent control valves Typical 16:1 turndown ratio No straight inlet/outlet duct run requirements

Laboratory Airflow Control Devices Control Valve Fundamentals Mechanical Pressure Independence Laboratory Airflow Control Devices Mechanical Operation Venturi Valve Expanded spring – increased airflow area Compressed spring – reduced airflow area Airflow remains constant – Damper position constant

Flow and Pressure Ranges Laboratory Airflow Control Devices Flow and Pressure Ranges

Laboratory Airflow Control Devices Presentation Title Version 00/00/00 Laboratory Airflow Control Devices Operational Range Valve Size Standard Accuracy Damper Control Valves Units Min. Flow Max. Flow Turndown Ratio Size 8 CFM 160 800 5:1 Size 10 225 1350 6:1 Size 12 350 2100 Size 14 500 3000 Operation Pressure in. w.c. >0.01 0.01 Copyright© 2012, All Rights Reserved - Price Industries

Laboratory Airflow Control Devices Presentation Title Version 00/00/00 Laboratory Airflow Control Devices Operational Range Valve Size High Accuracy Damper Control Valves Units Min. Flow Max. Flow Turndown Ratio Size 8 CFM 80 800 10:1 Size 10 120 1300 Size 12 180 1800 Size 14 250 2500 Operation Pressure in. w.c. >0.01 0.15 Copyright© 2012, All Rights Reserved - Price Industries

Laboratory Airflow Control Devices Presentation Title Version 00/00/00 Laboratory Airflow Control Devices Operational Range Valve Size Units Low Pressure Venturi Valve Medium Pressure Venturi Valve Min. Flow Max. Flow Turndown Ratio Size 8 CFM 35 500 14:1 700 20:1 Size 10 50 550 11:1 1000 Size 12 90 1200 13:1 1500 16:1 Size 14 200 1400 7:1 2500 12:1 Operation Pressure in. w.c. 0.3-3.0 0.6-3.0 Copyright© 2012, All Rights Reserved - Price Industries

Laboratory Airflow Control Devices Operation Pressure 08.12.2014

Control Methods and Accuracies Laboratory Airflow Control Devices Control Methods and Accuracies

Laboratory Airflow Control Devices Control Methods Closed Loop Control – Blade Damper Control Valve A closed loop or feedback control measures actual changes in the controlled variable and actuates the controlled device to bring about a change. * Airflow Control Methods ** Velocity Pressure Vortex Shedding Thermal Dispersion *2005 ASHRAE Handbook – Fundamentals of Control, Chapter 15 ** ASHRAE Laboratory Design Guide 2nd Edition; 2016, Chapter 11 - Controls

Laboratory Airflow Control Devices Control Methods Velocity Pressure * Averaging pitot tubes, flow crosses, and orifice rings are examples of devices that measure and may amplify the velocity pressure ±5% accuracy can be read from the flow sensors down to 140 fpm (0.71 m/s) ** Pressure transducers have several types of errors that should be considered Overall airflow sensing accuracy combines the effects of the probe and the pressure transducer. *ASHRAE Laboratory Design Guide 2nd Edition; 2016, Chapter 11 – Controls **ASHRAE Research Project RP-1353

Laboratory Airflow Control Devices Control Methods Velocity Pressure Error Example 2” Transducer w/ 0.50% Error of Full Scale. CFM Actual VP* Transducer Error Measured VP Measured CFM Error 1000 0.4522 0.01 0.4622 1011 1.1 % 500 0.1131 0.1231 522 4.3 % 200 0.0181 0.0281 249 24.5 % 120 0.007 0.0165 191 59.2 %

Laboratory Airflow Control Devices Control Methods Velocity Pressure Error Example 2” Transducer w/ 3% Error of Reading. CFM Actual VP* Transducer Error Measured VP Measured CFM % Flow 1000 0.4522 0.0136 0.4658 1015 1.49 % 500 0.1131 0.0034 0.1165 507 200 0.0181 0.0005 0.0186 203 120 0.007 0.0002 0.0067 122

Laboratory Airflow Control Devices Control Methods Vortex Shedding* Vortex shedding devices measure airflow by measuring the pressure pulses or vortices formed on the leeward side of an obstruction in the airflow and calculating the airflow ±2.5% to 10% accuracy can be read from vortex shedding sensors down to 450 fpm Response time for vortex shedders is typically slower than that of velocity pressure sensors. *ASHRAE Laboratory Design Guide 2nd Edition; 2016, Chapter 11 – Controls

Laboratory Airflow Control Devices Control Methods Thermal Dispersion* Thermal dispersion devices measure airflow through the use of thermistors in the airstream. ±3% of reading accuracy can be read from thermal dispersion sensors down to 50 fpm check the manufacturer’s accuracy and speed of response to changes in airflow as all thermal dispersion devices do not have the same accuracy and speed of response. *ASHRAE Laboratory Design Guide 2nd Edition; 2016, Chapter 11 – Controls

Laboratory Airflow Control Devices Airflow Control Concepts Flow Characteristics of the Blade Damper Control Valve In a closed loop flow control application, accuracy depends mainly on the airflow transducer but the resolution of the blade damper will greatly impact the flow measurement accuracy at low flows. 100% “Quick opening” characteristic Flow 0% Closed Full Open Position

Laboratory Airflow Control Devices Airflow Control Concepts Open Loop Control – Venturi Valve Control An open-loop control does not have a direct link between the value of the controlled variable and the controller. An open-loop control anticipates the effect of an external variable on the system and adjusts the set point to avoid excessive offset. * Potentiometer *2005 ASHRAE Handbook – Fundamentals of Control, Chapter 15

Laboratory Airflow Control Devices Presentation Title Version 00/00/00 Laboratory Airflow Control Devices Airflow Control Concepts No Airflow sensor – airflow is mapped to control arm position Control: Drives to required airflow which is known position Copyright© 2014, All Rights Reserved - Price Industries

Laboratory Airflow Control Devices Airflow Control Concepts Factory Valve Calibration 48 point characterization NVLAP Accredited N.I.S.T.* traceable +/- 5% accuracy Calibrated Flow Range Error 30 scfm to < 100 scfm 4.0% 101 scfm to < 250 scfm 2.5% 251 scfm to < 5000 scfm 1.4% *National Institute of Standards and Technology Factory Valve Calibration 48 point characterization N.I.S.T.* traceable equipment +/- 5% accuracy

Laboratory Airflow Control Devices Airflow Control Concepts Flow Characteristics of the Venturi Valve In an open loop application, flow control depends entirely on the flow versus position relationship of the valve but control resolution is improved at low flows. 100% “Stable opening” characteristic Flow 0% Closed Full Open Position

Laboratory Airflow Control Devices Speed of Response

Laboratory Airflow Control Devices Speed of Response Actuator Speed No Hoods  Standard-Speed (90 sec. typical) Hoods  High-Speed (< 4 sec. typical)

Laboratory Airflow Control Devices PTP 3200 Critical Controls January 5, 2014 Laboratory Airflow Control Devices Speed of Response Copyright© 2015, All Rights Reserved - Price Industries

Laboratory Airflow Control Devices Speed of Response Potentiometer Potentiometer Control Arm

Laboratory Airflow Control Devices Speed of Response ANSI Z9.5 – 2012 Section 6.5.3.2 VAV Response shall be sufficient to increase or decrease flow within 90% of the target flow or face velocity in a manner that does not increase potential for escape A response time of <3 sec. after completion of the sash movement is considered acceptable for most operations. Faster response times may improve hood containment following the sash movement.

Laboratory Airflow Control Devices Speed of Response ANSI Z9.5 – 2012 Section 6.5.3.2 VAV Response shall be sufficient to increase or decrease flow within 90% of the target flow or face velocity in a manner that does not increase potential for escape A response time of <3 sec. after completion of the sash movement is considered acceptable for most operations. Faster response times may improve hood containment following the sash movement.

Laboratory Airflow Control Devices Speed of Response ASHRAE 110-1995 - Section 6.4 The sash shall be fully opened in a smooth motion at a velocity between 1.0 ft/s and 1.5 ft/s. The time it takes from the start of the sash movement until the sash reaches the top and the time it takes from the start if the sash movement until the face velocity reaches and maintains, within 10%, the design face velocity shall be recorded

Laboratory Airflow Control Devices Speed of Response ASHRAE 110-1995 - Section 6.4 The sash shall be fully opened in a smooth motion at a velocity between 1.0 ft/s and 1.5 ft/s. The time it takes from the start of the sash movement until the sash reaches the top and the time it takes from the start if the sash movement until the face velocity reaches and maintains, within 10%, the design face velocity shall be recorded

Laboratory Airflow Control Devices Speed of Response NEBB Fume Hood Performance Testing - Section 9.3 VAV hoods are also to be tested to determine response time to return to a near steady state condition after a change in sash position. When changing the sash position, use a smooth continuous motion and move the sash at a rate of approximately 1.5 ft/s. Measure, record and report the VAV Speed of Response Time to first obtain a velocity equal to 90% of the baseline for each iteration.

Laboratory Airflow Control Devices Speed of Response NEBB Fume Hood Performance Testing - Section 9.3 VAV hoods are also to be tested to determine response time to return to a near steady state condition after a change in sash position. When changing the sash position, use a smooth continuous motion and move the sash at a rate of approximately 1.5 ft/s. Measure, record and report the VAV Speed of Response Time to first obtain a velocity equal to 90% of the baseline for each iteration.

Laboratory Airflow Control Devices Speed of Response 0.8 Seconds Venturi Valve – Time from completion of sash movement *Results from testing completed at Engineered Air Balance Laboratory, Houston - 2014

Laboratory Airflow Control Devices Speed of Response 2.5 Seconds Venturi Valve – Time from start of sash movement *Results from testing completed at Engineered Air Balance Laboratory, Houston - 2014

Laboratory Airflow Control Devices Speed of Response 1.25 Seconds High Accuracy Control Valve– Time from completion of sash movement *Results from testing completed at Price Research Center North, Winnipeg - 2016

Laboratory Airflow Control Devices Speed of Response 3.1 Seconds High Accuracy Control Valve– Time from start of sash movement *Results from testing completed at Price Research Center North, Winnipeg - 2016

Laboratory Airflow Control Devices Maintenance

Laboratory Airflow Control Devices Maintenance Flow Measurement vs. Position Feedback

Laboratory Airflow Control Devices Maintenance No risk of airflow sensor buildup/interference

Laboratory Airflow Control Devices Airflow Sound

Laboratory Airflow Control Devices Airflow Sound Valve Size Flow (CFM)** Terminal Discharge NC Value* Terminal Radiated NC Value * Venturi Discharge NC Value* Venturi Radiated NC Value* Size 8 400 21 31 23 Size 10 750 25 37 29 Size 12 900 27 32 24 Size 14 1500 26 41 44 *Test data obtained in accordance with AHRI Standard 880-2011 *NC values are calculated based on typical attenuation values outlined in Appendix E, AHRI Standard 885-2008 ** Flow measurements taken at 1.5 in.W.C.

Material Options and Coatings Laboratory Airflow Control Devices Material Options and Coatings

Laboratory Airflow Control Devices Material Options and Coatings Aluminum Construction Aluminum valve body and cone construction Stainless steel internal hardware PTFE Teflon coated center shaft Clean air or non-corrosive applications

Laboratory Airflow Control Devices Material Options and Coatings Phenolic Coating - Class 1 Aluminum valve body and cone construction Phenolic coated venturi body and cone Stainless steel internal hardware and support brackets PTFE Teflon coated center shaft Typical for most fume hood applications

Laboratory Airflow Control Devices Material Options and Coatings Phenolic Coating – Class 2 Aluminum valve body and cone construction Phenolic coated venturi body, cone and support brackets PFA Teflon coated stainless steel internal hardware PFA Teflon coated center shaft No exposed metal Chloric Acids Bromine Sodium Bisulfate

Laboratory Airflow Control Devices Material Options and Coatings PVDF Coating Aluminum valve body and cone construction Kynar® coated venturi body, cone and support brackets PFA Teflon coated stainless steel internal hardware PFA Teflon coated center shaft Used in extremely corrosive applications: No exposed metal Nitric Acid Hydrofluoric Acid Sodium Hydroxide

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