Sciencemadness Discussion Board

NFPA Diamond inconsistencies

Delta-R - 30-11-2020 at 01:49

So I’ve been updating my chemical inventory spreadsheet to add an SDS link and a quick NFPA reference column. Anyway, I noticed somewhere around the c’s that different SDS’s can give different NFPA ratings for the same chemical. This really started to bother me by the time I got to the m’s - just for example: The first SDS I found is for Mg metal turnings and ribbon, >90% and lists the NFPA info as Health:0, Fire:1, Reactivity:1, and No Water, the next is for Mg Ribbon >99%, and lists it as 1,1,1 no water and the last one is for Mg turnings >90% and lists it as 2,3,2 no water!

Considering the scale is only 0 to 4, the difference between 0 and 2 or 1 and 3 is huge. What’s the deal? This keeps coming up again and again. How does one decide which to use? Do you just go with the most conservative rating and call it a day or what?

macckone - 30-11-2020 at 03:04

For magnesium turnings, it depends on the size of the turnings as well as impurities.
coiled magnesium ribbon as shipped is unlikely to light even in a pretty strong fire.

There are also differences in 'as shipped' vs 'in bulk'.
500kg of magnesium turnings is clearly more dangerous than 500g which is more dangerous than 25g (the usual ribbon pack size).

The NFPA rating is designed for a room with a single or small group of chemicals stored in bulk vs a lab where the placard should probably be all 4s.
And it is a guide for fire fighters entering a room that is presumably on fire.
The NFPA 704 diamond is supposed to have 6 inch high numbers and be a minimum of 15 x 15 inches.
It really isn't designed for general safety data for day to day use.

OSHA has a better harmonized standard for work place hazards but many SDS are old and don't use the new standards.

Fyndium - 30-11-2020 at 06:13

This is quite true. Firefighting have different priorities than chemists.

The labels of chemical bottles would contain a lot more data about the stuff if they were made in mind of chemistry.

ShotBored - 30-11-2020 at 08:38

Quote: Originally posted by Delta-R  
So I’ve been updating my chemical inventory spreadsheet to add an SDS link and a quick NFPA reference column. Anyway, I noticed somewhere around the c’s that different SDS’s can give different NFPA ratings for the same chemical. This really started to bother me by the time I got to the m’s - just for example: The first SDS I found is for Mg metal turnings and ribbon, >90% and lists the NFPA info as Health:0, Fire:1, Reactivity:1, and No Water, the next is for Mg Ribbon >99%, and lists it as 1,1,1 no water and the last one is for Mg turnings >90% and lists it as 2,3,2 no water!

Considering the scale is only 0 to 4, the difference between 0 and 2 or 1 and 3 is huge. What’s the deal? This keeps coming up again and again. How does one decide which to use? Do you just go with the most conservative rating and call it a day or what?


Going off what the other guys said before me, thats why i think the new GHS system implemented the GHS pictograms and are kind of eschewing the NFPA diamond....The GHS pictograms, in addition to having the SDS info, should for the most part tell chemists what to look for when working with these chemicals.