goldstar
Senior Member
- Location
- New Jersey
- Occupation
- Electrical Contractor
Just venting (no pun intended). I’ve said this many times on this Forum – “You have to pay for your education”.
I’m always amazed when a fire inspector cannot give you a detailed and accurate description of how a commercial hood extinguishing system should function, aside from the obvious – it puts out the fire. Wouldn’t it be nice if you could walk into your local Building Dept., ask for a list of requirements for a hood extinguishing system and have them produce a master list so that all trades doing their respective installs can be on the same page ? I made it a point to ask questions up front at the Bldg. Dept. related to the electrical work but received little or no correct info. BTW, neither the BI or EI were in at the time.
Anyway, I recently wired two systems at the same facility where cooking appliances were installed. Here's the way it went :
Scenario # 1
This building was originally a house with one kitchen and had a gas operated range/oven. Seemed pretty straight forward to me. However, no one explained to me that the make-up air fan HAD TO come on at the same time as the exhaust fan. It wasn’t optional and I had chosen to install separate switches for each fan. But, that was an easy fix – I abandoned the s-p switch for the make-up air fan and installed a 2-pole switch for the exhaust and make-up air fans. Both units were fed from the same breaker (lesson # 1).
The hood extinguishing company installed a mechanical cable that closed the gas valve if the manual station was pulled. Voila, I’m done ! Not so fast said the building inspector – see that thermostat on the hood ? That has to be wired IN PARALLEL with the exhaust fan switch in the event that someone forgets to manually turn on the exhaust fan while cooking (lesson # 2). But what temperature should it be set at ? No one knows – I set it at 160 degrees. I’m sure I’ll be proven wrong on that as well (That will be another lesson I’m sure).
I set up a multi-pole relay (in its own cabinet) to activate or deactivate fans and shut off the hood light in the event of a dump (I believe I got that info here in the Forum). There were two ½” KO’s in the extinguisher panel for wire or conduit entry. I activated my relay via an MC cable using one of those KO’s and a SPDT micro-switch inside the extinguishing panel. The alarm guy used the other KO and switch to trip the FA system. The day before the inspection I just happened to stop by and low and behold the extinguisher guy literally pulled my (live) MC cable out of the KO because he needed THAT KO for the gas shut-off cable (I take another hit on the chin and corrected it). But, everything is great right ! Not so fast said the extinguisher guy. In order for us to maintain the UL listing on the extinguishing panel you cannot make splices inside our panel. Both you and the alarm guy have to install JB’s outside our panel and make your connections there (lesson # 3).
I had pulled an electrical permit before anyone else did any work, including the hood guys. They had trouble up front because they didn’t submit engineer approved drawings for the hoods and eventually failed inspection for not having correctly sized the hoods (that they already installed without a permit). Not my problem
Scenario # 2
This building had two electric range-ovens in separate cooking areas that were back to back and had a common hood with common exhaust and make-up air fans. Everything I had to correct in this building was exactly the same as the building in Scenario # 1 except that I had set up 3-way switches for the fans because the ovens were in separate rooms. That meant I had to rewire the relay panel in addition to changing the fan switches to 2-pole. Range ovens were shut down via 50 amp shunt trip breakers and each hood had its own thermostat before meeting up with the common duct.
All in all I spent (at my own expense) about 3-4 hours plus the cost of switches and wire to correct these mistakes. It would have been nice if someone, other than the building inspector, knew the proper operation of the system. I’ll say it again, you have to pay for your education.
I’m always amazed when a fire inspector cannot give you a detailed and accurate description of how a commercial hood extinguishing system should function, aside from the obvious – it puts out the fire. Wouldn’t it be nice if you could walk into your local Building Dept., ask for a list of requirements for a hood extinguishing system and have them produce a master list so that all trades doing their respective installs can be on the same page ? I made it a point to ask questions up front at the Bldg. Dept. related to the electrical work but received little or no correct info. BTW, neither the BI or EI were in at the time.
Anyway, I recently wired two systems at the same facility where cooking appliances were installed. Here's the way it went :
Scenario # 1
This building was originally a house with one kitchen and had a gas operated range/oven. Seemed pretty straight forward to me. However, no one explained to me that the make-up air fan HAD TO come on at the same time as the exhaust fan. It wasn’t optional and I had chosen to install separate switches for each fan. But, that was an easy fix – I abandoned the s-p switch for the make-up air fan and installed a 2-pole switch for the exhaust and make-up air fans. Both units were fed from the same breaker (lesson # 1).
The hood extinguishing company installed a mechanical cable that closed the gas valve if the manual station was pulled. Voila, I’m done ! Not so fast said the building inspector – see that thermostat on the hood ? That has to be wired IN PARALLEL with the exhaust fan switch in the event that someone forgets to manually turn on the exhaust fan while cooking (lesson # 2). But what temperature should it be set at ? No one knows – I set it at 160 degrees. I’m sure I’ll be proven wrong on that as well (That will be another lesson I’m sure).
I set up a multi-pole relay (in its own cabinet) to activate or deactivate fans and shut off the hood light in the event of a dump (I believe I got that info here in the Forum). There were two ½” KO’s in the extinguisher panel for wire or conduit entry. I activated my relay via an MC cable using one of those KO’s and a SPDT micro-switch inside the extinguishing panel. The alarm guy used the other KO and switch to trip the FA system. The day before the inspection I just happened to stop by and low and behold the extinguisher guy literally pulled my (live) MC cable out of the KO because he needed THAT KO for the gas shut-off cable (I take another hit on the chin and corrected it). But, everything is great right ! Not so fast said the extinguisher guy. In order for us to maintain the UL listing on the extinguishing panel you cannot make splices inside our panel. Both you and the alarm guy have to install JB’s outside our panel and make your connections there (lesson # 3).
I had pulled an electrical permit before anyone else did any work, including the hood guys. They had trouble up front because they didn’t submit engineer approved drawings for the hoods and eventually failed inspection for not having correctly sized the hoods (that they already installed without a permit). Not my problem
Scenario # 2
This building had two electric range-ovens in separate cooking areas that were back to back and had a common hood with common exhaust and make-up air fans. Everything I had to correct in this building was exactly the same as the building in Scenario # 1 except that I had set up 3-way switches for the fans because the ovens were in separate rooms. That meant I had to rewire the relay panel in addition to changing the fan switches to 2-pole. Range ovens were shut down via 50 amp shunt trip breakers and each hood had its own thermostat before meeting up with the common duct.
All in all I spent (at my own expense) about 3-4 hours plus the cost of switches and wire to correct these mistakes. It would have been nice if someone, other than the building inspector, knew the proper operation of the system. I’ll say it again, you have to pay for your education.
