How to Protect Ducting from Overpressure

[invent11]

Our ducting is designed to +10 w.g., as a part of our system is a dryer. I noticed that shutoff pressure for dryer's blower is 15 w.g. My question is how to protect ducting in case of dryer/blower being started while downstream dampers are closed? What method or device you recommend? Furthermore if i do not provide overpressure protection what is the worst thing that can happen?
Thanks for your input.

 

[urgross]

Having a high pressure limit, low pressure limit, smoke/fire, and freezstat on emergency circuit is pretty much standard, though 10 IWG is certainly not standard. You need a dP sensor, on preferred dedicated circuit, to shut down the unit at excessive pressure.

 

[DrRTU]

To avoid controls and wiring, use a greenheck PRAD damper sized for 10" and your c[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1463058729/tips/Greenheck_Prad_cg6390.pdf[/url]fm.

 

[317069]

nothing would happen, don't worry.

 

[urgross]

DrTRU,

Good suggestion, if you don't have a building automation system, though the G60 seems cheesy.

 

[EnergyProfessional]

DrRTU gave you the proper solution. You need to size it based on manufacturer recommendation.

i wonder, you say shut-off pressure is 15", i suppose you mean at no-flow? does your duct have dampers at all? If there isn't really something to damper it off (reduce flow to 0), there wouldn't be a danger of fan to produce maximum pressure.

You also can use a pressure sensor that stops the fan, but a PRAd damper seemms simple and reliable. BAS also can lose control over the fan if someone puts the VFD in bypass, so there is that.