I have a question regarding the need to provide electrical classification for a building using Class 1A flammable liquids.

For this building, 4 gallons could be out in use (located anywhere in the building). The MAQ is 10 gallons. I have discussed this with NFPA 30 committee, the manufacturer, and the AHJ (who is a knowledgeable FPE). They have all determined that even if the MAQ is not exceeded, electrical classification is required if a flammable/explosive mixture could be present.

The NFPA 30 staff directed me to a provision in NFPA 497, Section 5.5, that if the materials will not reach 25% of the lower flammable limit (LFL), this could be utilized to justify not providing classified electrical fixtures.

Does anyone know how to do this calculation, or know of firms that can be hired to do this?

I am an FPE and do not know how to perform it, and I have spoken with other FPE’s who also are not aware. The gentleman I spoke with at NFPA 30 agreed it would be by an industrial hygienist or a chemical engineer and not an FPE.

But does anyone know any that can be hired for a one-off calculation, or have a place where I could learn how to perform it myself (NFPA reference, SFPE article, course, etc.?).

Thank you!

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I need to label some deflagration vents as "out-of-service" since they are not being maintained properly and are currently not needed from a code standpoint (as the use of the room has changed). We do not want to remove them as the room may be changed back one day depending on research needs.

Does anyone know if there is a code reference that points to the size of the letters or font type for an out-of-service-tag?

In this case a tag is not practical since it needs to go on a flat panel. I know there are such requirements for exit and "no exit" signs, but I'm not aware of any code guidance for out-of-service signs. Thanks in advance for any feedback.

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In which of the following scenarios is neither explosion protection nor suppression system required? 
a. Flammable paint warehouse mixing rooms where open transfer of paint occurs
b. Dust ventilator equipment where the dust density can be above its lower flammability limit
c. Mechanical room where service equipment is subject to explosion
d. All of the above require either explosion protection or suppression systems

Solution | Posted 10/05/20

Has anyone seen the International Fire Code Chapters 53 and 58 applied to natural gas installations in addition to the Fuel Gas Code?

IFC Chapter 53 is Compressed Gasses and Chapter 58 is Flammable Gasses.

It's technically a gas at standard temperature and pressure with a boiling point below 68 deg F at 14.7 psi and flammable range of 5% to 17% by volume in air. Natural gas appears to be subject to these requirements, but I've never seen it this way in practice. 

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We have a closed ammonia refrigeration system for a large cooler/freezer. The refrigeration equipment is located in a separate mechanical room. Total amount of ammonia is less than 10,000 lbs.

My question is explosion control per Section 911 of the International Fire Code required for the refrigeration mechanical room?

I am reading different interpretations on whether ammonia is considered a flammable gas, most say it is technically not a flammable gas but can burn and/or explode.

I'm interested in hearing everyone's take. Thanks.

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What occupancy type would you consider a building being used for powder coating of metal chassis?

The IBC lists F-2 (Low-Hazard Factory Industrial) as the occupancy for metal fabrication and assembly and basically the fabrication or manufacturing of non-combustible materials in which the processes do not involve a significant fire hazard.

Anything not listed as F-2 would be considered F-1 (Moderate-Hazard Factory Industrial).

In this building they bring in the metal chassis, send them through an oven to warm them up, then send them through another booth to standblast them. Then the chassis are powder-coated before going through a final oven to be cured.

In my opinion and past exeprience with powder coating it can be a pretty hazardous activity with explosive hazard and with finely divided particles. I do know the booth is pretty large for powder coating will need to have fire suppression. The big question is would be consider this building F-1 or F-2 requiring fire suppression throughout, as the building is well over 12,000 sqft in area. 

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An oil field site has a potential for detonation of an equivalent of 180 lb of TNT at its main plant. Determine most nearly the minimum distance where an adjacent oil storage tank would rupture at this energy.
a. 50 ft.
b. 80 ft.
c. 100 ft.
d. 150 ft.

Solution | Posted 10/14/19

Solution | Posted 09/26/19

​In which of the following scenarios is neither explosion protection nor suppression system required?
a. Flammable paint warehouse mixing rooms where open transfer of paint occurs
b. Dust ventilator equipment where the dust density can be above its lower flammability limit
c. Mechanical room where service equipment is subject to explosion
d. All of the above require either explosion protection or suppression systems

Solution | Posted 08/27/19

We manufacture dust collectors and pre-pipe fire sprinklers within them with a couple fusible fittings.

We pressure test the pipe at our shop, however, when a contractor connects to them in the field, are there any code/standard requirements to check the system for leaks after connecting to the system?

We put on our drawings that the contractor should test for leaks, however, we're trying to determine what requirements exist for this application.

​The problem we're running into is that the connection is supposed to be made and checked before installing cartridges. If a leak occurs, the contractor could address and not get the paper cartridges all wet with running water down at the floor. In this last case they didn't, and I'm trying to address future installation of systems and make sure the contractor checks for leaks. 

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I've taken technical writing courses and have experience working with MasterSpec, US Military specifications, vendor specifications, and various ownership standard specifications.

I'm giving an internal training to our younger staff and I'm particularly interested in opinions from contractors and vendors who regularly read a variety of specifications for bidding.

What advice would you give for those who write specifications? I'd be interested in helping train our staff as well as improve myself.

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