Propane Tank Clearance

[tryinghard]

I understand a propane storage tank (1000 gallon+/-) which will be used to serve a building as Class 1 Division 1, per (500-7(a)& FPN (1), is this correct?

A client is considering placing a switchboard within the same containment area (CMU block wall, no roof) as this propane tank. I advised against this due to 501-6.

Were can I find the minimum distance between the switchboard and propane storage tank?

 

[rbalex]

Re: Propane Tank Clearance

It appears you're using the 1999 NEC. That's fine, the principles will be the same.

Art 515 is generally applicable to your installation, assuming the distribution to the facility is by pipeline. The primary issue is the propane receiving method. I am assuming it is not piped in.

Look at Table 515-2 and especially review the requirements for the containment area (Tanks - Aboveground). Look at other potential applications for from the entire Table, especially fill ports and pressure relief vents.

Propane is heavier than air but it is nevertheless a relatively light gas so it has a tendency to "cloud" around potential sources, like the fill port and vents. It also collects in low points. Generally, well maintained piping can be ignored.

An experienced, qualified person should fully document the area classification per 500-3(b.)Note: this is a legal requirement per OSHA Process Safety Management.

Having said all this, I definitely recommend against switchgear in a common containment area.

 

[tryinghard]

Re: Propane Tank Clearance

Yep, 1999 in California. The receiving method is by delivery truck. I have advised the project superintendent the distance needs to be qualified by the fire marshal or others qualified to make this judgment. We will not be installing this in the same containment area.

Thanks for your help