Fire Station Apparatus Bay Ventilation

[Jordan Fish]

Hello Everyone - first time poster here. I am a mechanical engineer from Baton Rouge, LA (Geaux Tigers!).

I have recently been reviewing the ventilation requirements for a fire station's apparatus bay. The bay is to be used for storing the vehicles only, i.e. no repair, fueling, etc. I have reviewed the following adopted code versions in my state: NPFA 101-2015, NFPA 88A-2015, IBC-2015, and IMC-2015. The AHJ in my state has also issued an interpretation that extends the Private Garage applicability to up to 3,000 square feet in lieu of the 1,000 square feet stated in the IBC. I have two separate sites I am designing with one of the apparatus bays being 2,000 square feet and the other is 5,000 square feet. Currently, the smaller bay is classified as a Group U occupancy and is being considered a Private Garage. The larger is Group S-2 and is being considered an Enclosed Parking Garage.

The conclusion I get from all of these codes is that some form of continuous ventilation is required in the apparatus bay. Below is what I have found in each code that states a ventilation rate.

NPFA 88A, 6.3.1: All enclosed parking structures shall be ventilated by a mechanical system capable of providing a minimum of 1 CFM/sq. ft. during hours of normal operation.

IMC 2015, Table 403.3.1.1 for Private and Public Garages - 0.75 CFM/sq. ft.

IMC 2015, Section 404 for Public Enclosed Parking Garages - You can provide CO and NO2 monitoring to reduce the rate to 0.05 CFM/sq.ft during times that the CO and NO2 levels are "normal". If CO or NO2 alarm trips, the rate increases to 0.75 CFM/sq. ft.

I have discussed this with many colleagues and have received a mixed bag of answers. Some have not ventilated at all, some provide the CO/NO2 monitors with no constant exhaust, some provide "comfort" ventilation fans with manual control....

My thought is that if I have to compare the NFPA 88A to the IMC 2015 and take the most stringent, I'll be ventilating at 1 CFM/sq. ft. year round.

Any of your help and experience will be greatly appreciated!

 

[cda]

Welcome


A lot of research !!

So which code do you have to design to!!


Most stations now use individual vehicle extractors

Suggest finding out if this one will,,,


And does that change the equation?!

 

[Jordan Fish]

As always with code research, the more you look, the deeper it goes!

My understanding has always been that the most stringent code has to be applied. In LA, we have adopted NFPA 101-2015, which by way of Chapter 2, requires you to comply with NFPA 88A-2015. 2015 International Codes are also adopted here, so the code official always defaults to the most stringent when a question arises.

The owner/architect is explicitly wanting to avoid the vehicle extractors. I was given the occupancy classification and from there starting digging to get to the point I am at now.

Even if we did do the vehicle extraction setup, the code sections appear to still require the continuous exhaust, i.e. I didn't see any exceptions for the ventilation requirements.

Thanks for the reply.

 

[Jordan Fish]

Update to this - it appears the IMC does not require the ventilation per 502.14 if used for drive-in, park, drive-out usage as we are doing. This still does not solve the issue with NFPA 88A requiring the ventilation.

 

[cda]

hum

owner does not want it?

As in government?

Removing carcinogens is a big topic lately, which includes trying not to inhale exhaust.

 

[Builder Bob]

Explore alternate means and methods - as a retired fire fighter for 32 years, we caught hell trying to keep the apparatus bays above freezing in the winter - continuous exhaust means that the entity is paying utility bills to heat out side air........ constant air exchange in space - see if they (the AHJ) will accept co monitoring to initiate exhaust fans for ventilation - also be sure to provide direct exhaust ductwork to exhaust with pressure switch for a closed exhaust ventilation system for when the trucks crank up, the exhaust tube remains attached to the vehicle until it leaves the station. Be sure to incorporate a retraction system for the exhaust tubes so they do not impede the ability of the door closures to shut the doors for fire station security (yes people rob the fire stations while the occupancy are protecting the public... been there, got the tattoo - BTW the city insurance does not cover personnel belongings that are lost - cell phones, laptops, etc.

 

[TheCommish]

the consensus now is the diesel fume should have point source capture at the tale pipe, newer thing is the garage should be at negative pressure from other spaces in the building also. There is a huge movement in the Fire Service for cancer prevention and keeping contaminates minimized

Asst. Chief
Curtis Meskus