There are more than 380 substances with IDLH limits. View the current list of substances with IDLH. You can also find IDLH values in CAMEO Chemicals or in the online version of the NIOSH Pocket Guide(link is external).
IDLH limits were primarily established to aid in making informed decisions about respirator use. Above the IDLH, only supplied air respirators should be used; below the IDLH, air purifying respirators may be used, if appropriate. Until 1994, an exposure duration of 30 minutes was associated with the IDLH. However, the current definition lacks an associated exposure duration; workers should not be in an IDLH environment for any length of time unless they are equipped and protected to do so.
When it comes to using IDLH valves in our safety designs, you should know that the IFC mentions IDLH in seven (7) sections:
- 608.13.5,
- 608.14,
- 916.8,
- 2703.13.2,
- 5303.16.10,
- 6004.2.2.10,
- 6004.2.2.7.2