WesR
Member
- Location
- Phoenix, AZ, USA
I am trying to determine the Group for various chemicals; I am refering to the Groups of Class I chemicals in NFPA 70 article 500. I can see the Groups are defined by either MESG or MIC. The available information I have for these chemicals are the MSDS's. I have never seen an MSDS that has either MESG or MIC listed. Information that is sometimes provided on MSDS's includes AIT, UFL, and LFL. For those which I have such information, how might I use this information to determine the Group as suggested in A.5.8.2.5 of NFPA 497? By the way, I lack "experience-base data indicating equivalency to atmoshpheres providing similar hazards". Also, for chemicals which I do not have AIT, UFL, and LFL, how would I determine the Group?
I have guessed what some answers might be and prepared some responses:
Answer:
Refer to Table 4.4.3 in NFPA 497.
Response:
None of my chemicals are listed in that table.
Answer:
Perform tests to determine either MESG or MIC.
Response:
I need to determine the Group for about 20 chemicals and I would likely need to have someone else perform these tests. How much would this cost? Also, how long would this take? How do I provide them with the chemicals (put them in the mail?)?
Answer:
Try to find MESG or MIC results for your chemicals from tests that others have already performed.
Response:
Is there a convenient resource to do this or must I search the entirety of the internet?
Answer:
Contact the manufacture of those chemicals and ask for this information.
Reponse:
And if they don't have this information?
Thank you for any help. If more information is needed, please ask.
I have guessed what some answers might be and prepared some responses:
Answer:
Refer to Table 4.4.3 in NFPA 497.
Response:
None of my chemicals are listed in that table.
Answer:
Perform tests to determine either MESG or MIC.
Response:
I need to determine the Group for about 20 chemicals and I would likely need to have someone else perform these tests. How much would this cost? Also, how long would this take? How do I provide them with the chemicals (put them in the mail?)?
Answer:
Try to find MESG or MIC results for your chemicals from tests that others have already performed.
Response:
Is there a convenient resource to do this or must I search the entirety of the internet?
Answer:
Contact the manufacture of those chemicals and ask for this information.
Reponse:
And if they don't have this information?
Thank you for any help. If more information is needed, please ask.
