INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Spray booths and their exhaust ducts

Spray booths and their exhaust ducts

(OP)
As per NFPA 13 2013, 22.4.1.2 "exception" one can design to Ordinary Hazard 2 for powder coating but does not get into the ductwork portion of the design . I would imaging the 30gpm/15 psi would still apply but seems to defeat the purpose of the exception.
Also - I see that some treat the ductwork/stack 12'-0" max spacing run on the horizontal only. I interpret otherwise. Am I missing something?

RE: Spray booths and their exhaust ducts

(OP)
Actually 33 - 9.4.6 of 2016 Clarifies the spacing within ducts to 12' horizontal and at the top of an exhaust riser to a maximum 24'. No clarification on calcs within a duct on OH2 permissible systems though.

RE: Spray booths and their exhaust ducts

I read it the same way as you Shred... duct sprinkler sprinkler requirements are in a completely separate section from the booth requirements, and there doesn't seem to be any reduction given for powder coating operations.

OH-2 in the booth is still a significant reduction, in terms of piping and number of sprinklers though. 5.6's instead of 8's or 11.2's saves the contractor some $$, more still if you can use the 15' max spacing and eliminate an entire branch line.

RE: Spray booths and their exhaust ducts

FYI because I'm assuming your hazard has ductwork: Most powder coating booths do not have an exhaust vent stack which are required for flammable spray finishing booths. The newer powder coating booths have an internal filter system within the plenum that captures the resin powder and discharges it into a filter pan. If a system has a duct system, it's probably routed to a dust collection system. The atmosphere, if properly designed, is operating at < 50% of the Minimum Explosive Concentration (MEC) of the dust. This allows the duct to be classified as General Purpose exhaust under most mechanical codes and eliminates the need for sprinklers.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close