Hello – Happy Friday! Today’s post comes to you from Eric Nette, Engineer in the Industrial and Chemical Engineering Department, at NFPA. Special thanks to Eric for his contribution to this blog while I am out on maternity leave, and discussing one of the many important subjects addressed in the Fire Code.
Good morning! This week on Fire Code Fridays we will be discussing Liquefied Petroleum Gas (LP-Gas) and the newest edition of NFPA 58. A commonly used LP-Gas would be propane. NFPA 1 states:
22.214.171.124 The storage, use, and handling of liquefied petroleum gases (LP-Gas) shall comply with the requirements of this chapter; NFPA 58 and Sections 60.1 through 60.4 of this Code.
This makes it very important to stay up to date on your ancillary codes. NFPA 58 was revised last year to the 2017 edition of the code. This edition has several exciting and significant changes. I will try to summarize one of the more important changes, but it’s important to look into the new code to determine if any pertinent changes have occurred for your applications.
Some of the new items added to NFPA 58. 2017, were skid tanks and porta-pacs (a restructure of portable storage containers and portable container classification), changes to the requirements for vehicle barrier protection, and the allowances for containers less than 2 lbs. water capacity. More information on NFPA 58 can be found at www.nfpa.org/58 and a new food truck handout can be found at www.nfpa.org/foodtrucksafety. The food truck handout now includes a cross section of requirements/recommendations from 4 NFPA standards, including NFPA 58, with exact references on where each is found in each document. Additional requirements from NFPA 58, 2017 edition, will be extracted from NFPA 58 into the new section on portable cooking equipment in Section 50.7.
There is one major technical change to NFPA 58, 2017 edition, that although not included in NFPA 1 2018 edition directly, is important for users of NFPA 58 outside the scope of the Fire Code, to be aware of. NFPA 58 has in the past excluded containers in all transportation situations and deferred to the corresponding transportation authorities (DOT, FAA, Coast Guard, etc.). In this edition the committee struggled with allowing the filling of hot air balloon containers. These containers posed a challenge as they are widely filled safely by properly trained filling personnel but were completely unrecognized by NFPA 58. Several hot air balloon festivals were experiencing issues attaining filling services because propane suppliers did not want to accidentally violate the code.
Hot air balloon containers operate in a very different environment than that experienced by gas grill containers. Due to this operation the containers must be able to expel bursts of LP-Gas at a higher than normal altitude to operate the burner. The pilots depend on the burner to operate and steer the hot air balloon. Regular containers utilize an “Excess Flow Valve” that automatically operates if a large flow rate is experienced on the outlet of the container. This is a safety mechanism that is installed for those cases in which a line could break and expel a large flow rate of LP-Gas at once. Hot air balloon containers cannot utilize these valves without triggering them and accidentally turning off their burner mid-flight.
Under compression LP-Gas converts itself into a liquid. This is why sometimes when you turn on your gas grill cylinder it will get cold. For the LP-Gas to leave the cylinder it must convert from a liquid to a gas, which requires heat energy from its surroundings (called the autorefrigeration reaction). At higher than normal altitudes the environment around the containers is much cooler than it would be on the ground. Therefore the containers must be heavily insulated. The containers are inspected yearly by the federal aviation administration (FAA), but NFPA 58 requires regular cylinders to have all of their insulation/wrappings removed prior to filling to verify the lack of corrosion on the container. Corrosion on the cylinder has led to several incidents in the past (the most recent being the food truck explosion in Philadelphia). Removing these wrappings on a hot air balloon container can take up to an hour.
The NFPA 58 technical committee removed hot air balloon containers from the exclusions of the scope. The FAA regulations were also added to the list of container requirements, and their inclusion in the pilots log was added for filling requirements. These containers were excluded from the requirement for removing the wrappings/insulation for every fill and the pilot/crew are now allowed to assist in filling operations. The pilot/crew license requires training with LP-Gas filling. The refresher training for these licenses occurs at shorter intervals than required by NFPA 58 for regular filling operations. Again, the provisions for hot air balloons are excluded from NFPA 1 as they are outside the scope of a Fire Code. However, the provisions are important to understand for those jurisdictions who utilize NFPA 58 or may be trying to further understand the comprehensive set of changes to the newest edition of this Code.
Thanks again, Eric! Happy Friday, stay safe!