This has been a fun week with all the dialogue I have had with so many SAFTENG members; I only wish more were comfortable having these discussions online, but the fear of being traced back to an employer or being trolled by a lawyer I guess is a legitimate fear in our technical/risk profession. One of the most popular responses I have received is “why does it matter if the chemical has an NFPA 4 or 2… its a CAT 1 Flammable Gas and thus it is a PSM chemical… let them put what they want in the diamond – it matters not what the diamond says”. But it DOES MATTER what the NFPA 704 diamond says and here is a perfect example of why…
One client who has this CAT 1 Flammable Gas on-site has decided that their process was indeed a PSM covered process. So the management at the facility made the decision to reduce the inventory of the material so that they are well under the 10,000 pounds TQ. The safety manager was elated but was also quick to inform the engineering and operational management that this CAT 1 Flammable Gas still deserves respect and attention. This safety manager was one of those who was quick to correct the NFPA 704 Diamond on his tank from a “1” to a “4” – albeit not at the appreciation of his management group. Because the state where they are located has a State Fire Code based on the 2012 International Fire Code, the safety manager has a platform to use to ensure the process handling this CAT 1 Flammable gas has some minimum safety design(s). So what does this mean?
We have to remember, there is NO OSHA “FLAMMABLE GAS” standard that a safety professional can turn to when needing some guidance on what the minimum safety requirements are. Sure they can try and use 1910.102, .103, .110, etc. but those are specific to their flammable gas and we all know how some managers are quick to point out “proper application” of the standards. So this safety manager knew the IFC had some decent baseline design requirements that were applicable to his process handling this CAT 1 Flammable Gas… only one problem – his engineering manager was quick to point out that the SDS for this chemical says the NFPA Flammability Rating is a “2” – not a “4”, even though the SDS revision before says its a “4”. “The manufacturer knows best what the NFPA rating should be” he is told. This all matters because he wanted to use the IFC to drive good engineering practices for this material and the IFC uses the NFPA 704 “Degrees of Hazards” when establishing the requirements for Design and Construction of systems handling Hazardous Materials. The IFC specifically calls out Flammable and Health Degree of Hazards of “3” and “4” such that they REQUIRE additional design and construction specifications due to the increased hazards of these hazardous materials. Here is what the IFC 2015, Chapter 50 HAZARDOUS MATERIALS—GENERAL PROVISIONS says about this:
Where gases or liquids having a hazard ranking of:
Health Class 3 or 4
Flammability Class 4
Instability Class 3 or 4
in accordance with NFPA 704 are carried in pressurized piping above 15 pounds per square inch gauge (psig) (103 kPa)…
and
Supply piping and tubing for gases and liquids having a health-hazard ranking of 3 or 4 in accordance with NFPA 704 shall be in accordance with ASME B31.3…
Here is the full explanation of why the correct NFPA Diamond Degree of Hazard(s) matters…
(emphasis by me)
5003.2.2.1 Design and construction. Piping, tubing, valves, fittings and related components used for hazardous materials shall be in accordance with the following:
1. Piping, tubing, valves, fittings and related components shall be designed and fabricated from materials that are compatible with the material to be contained and shall be of adequate strength and durability to withstand the pressure, structural and seismic stress and exposure to which they are subject.
2. Piping and tubing shall be identified in accordance with ASME A13.1 to indicate the material conveyed.
3. Readily accessible manual valves or automatic remotely activated fail-safe emergency shutoff valves shall be installed on supply piping and tubing at the following locations:
3.1. The point of use.
3.2. The tank, cylinder or bulk source.
4. Manual emergency shutoff valves and controls for remotely activated emergency shutoff valves shall be identified and the location shall be clearly visible, accessible and indicated by means of a sign.
5. Backflow prevention or check valves shall be provided where the backflow of hazardous materials could create a hazardous condition or cause the unauthorized discharge of hazardous materials.
6. Where gases or liquids having a hazard ranking of:
Health Class 3 or 4
Flammability Class 4
Instability Class 3 or 4
in accordance with NFPA 704 are carried in pressurized piping above 15 pounds per square inch gauge (psig) (103 kPa), an approved means of leak detection and emergency shutoff or excess flow control shall be provided. Where the piping originates from within a hazardous material storage room or area, the excess flow control shall be located within the storage room or area. Where the piping originates from a bulk source, the excess flow control shall be located as close to the bulk source as practical.
Exceptions:
1. Piping for inlet connections designed to prevent backflow.
2. Piping for pressure relief devices.
5003.2.2.2 Additional regulations for supply piping for health-hazard materials. Supply piping and tubing for gases and liquids having a health-hazard ranking of 3 or 4 in accordance with NFPA 704 shall be in accordance with ASME B31.3 and the following:
1. Piping and tubing utilized for the transmission of highly toxic, toxic or highly volatile corrosive liquids and gases shall have welded, threaded or flanged connections throughout except for connections located within a ventilated enclosure if the material is a gas, or an approved method of drainage or containment is provided for connections if the material is a liquid.
2. Piping and tubing shall not be located within corridors, within any portion of a means of egress required to be enclosed in fire-resistance-rated construction or in concealed spaces in areas not classified as Group H occupancies.
Exception: Piping and tubing within the space defined by the walls of corridors and the floor or roof above or in concealed spaces above other occupancies where installed in accordance with Section 415.11.6.4 of the International Building Code for Group H-5 occupancies.
So as we can see, the NFPA 704 Diamond Degree of Hazard(s) matter. By the manufacturer’s stating this CAT 1 Flammable Gas has a “2” flammability hazard, it is NOT required to be managed as an actual flammable gas but rather as a flammable liquid – and there are DIFFERENCES between the degrees of hazard with a flammable liquid and a flammable gas. We do have the saving grace of Chapter 58 in the IFC that will dictate some special requirements for a “Flammable Gas” which the SDS will clearly state this material is such, but because of the confusion regarding the “2” vs. “4”, we could miss out on the critical controls listed above.