NFPA 33 - Sprinkler Requirement in Spray Booth 1

[ChrisConley]

I have a client with a Fibre Glass manufacturing facility. (Styrene Cross-Linked Composites Manufacturing). They've been tagged by the fire inspector as being deficient in NFPA 33 and some items of the Canadian National Fire Code.

My two questions are:

NFPA 33 calls for sprinkler protection in resin application areas for at least Ordinary Hazard, Group 2. Does this apply in a building does not require sprinkler protection? There is a fire protection system in place, but it isn't NFPA 13.

NFPA 33 calls for ventilation to reduce the concentration of the sprayed product to 25% of the LEL. The explanatory annex says: Tests of resin application areas have shown that the processes do not produce vapors that exceed 25% of the LEL. Resin application tests have also indicated that the maximum levels of vapor concentration are about 690 ppm for spray applications. The test were conducted in an enclosed area with no ventilation.

That sounds like no ventilation is actually required (other than the obvious).

I'd appreciate any input anyone has on NFPA 33 and Styrene Spray Booths.

 

[stookeyfpe]

Ordinary Hazard Group 2. See the NFPA 33 requirements for the manufacturing rigid thermoplastics.

Sprinkler protection is required for the building - however, the spray booth is not required.

Mechanical ventilation is required at an airflow rate of 1 CFM/square foot over the manufacturing area.

Have you evaluated the styrene monomer storage and organic peroxide storage?

 

[cdafd]

To me NFPA 33 gives you several fire protection options for the spray area, it does not have to be a fire sprinker system

see if stookey agrees with that point?

 

[ChrisConley]

We have evalulated storage volumes and they are building a fire rated storage area.

Where does the ventilation rate come from stookey? I was planning on using something along those lines, but didn't have a code reference to back it up.

I agree they don't need the booth, it's a convereted paint booth, which is the problem because the installation is being treated like a paint booth.

 

[stookeyfpe]

Chris,

Section 17.6.1 says mechanical ventilation is required in accordance in accordance with Chapter 7. The section exempts structures open on 3 sides but since you're in Canada, I doubt a lot of those buildings in a manufacturing environment exist.

In the US, we prescribed 1 CFM/Square Foot. Since you are in Canada, you only need to maintain the atmosphere below 25% LFL in air for styrene monomer. Annex Section 17.3 (2) states that during resin application, the vapor concentration for styrene monomer was measured at about 690 PPM. In this case, the atmosphere is below 25% LFL. Therefore, no mechanical ventilation is required.

You can also use this data as a basis for avoiding the installation of hazardous (classified) electrical equipment.

CDA, Section 17.3 is very clear: OH2 automatic sprinkler protection is required in the resin application area. In the storage area, the standard probably permits other types of protection.

 

[cdafd]

SORRY did not read the entire book

 

[ChrisConley]

My problem is now that the Canadian Code doesn't require sprinkler coverage, but treats the process like a paint booth and requires paint booth ventilation (which they don't meet completely). If I use an NFPA 33 argument that we don't require paint booth ventilation then the space needs to be sprinklered, or I can cherry-pick between the codes, which I don't think I want to do.

My recommendation will be to sprinkler the building with OH2 in the resin application area.

Thanks for the comments!

 

[chicopee]

If the resin is sprayed on the fibreglass cloth, you may also want to interlock the spray equipment and the ventilation system.