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respiratorcalc

Respirator selection

Formaldehyde respirator selectionHCHO (CH2O)

Resins/adhesives, particleboard & plywood, embalming/pathology, textiles, disinfectants; wood-products and healthcare industries.

OSHA PEL
0.75 ppm
TWA 8-hr (29 CFR 1910.1048; also STEL 2 ppm, action level 0.5 ppm)
NIOSH REL
0.02 ppm
TWA (carcinogen, Ca; also 15-min Ceiling 0.1 ppm)
IDLH
20 ppm
Molecular weight
30.03 g/mol

These are federal OSHA limits. The PEL shown is the federal OSHA value. About two dozen states run their own OSHA-approved plans, and some — notably California (Cal/OSHA) — enforce lower or additional exposure limits. If you work under a state plan, check your state's PEL and enter it as a custom limit in the calculator.

Cartridge (limited use): Formaldehyde-specific cartridge/canister — Olive band

An APR fitted with the correct cartridge is only adequate up to its MUC (below) — the cartridge must be able to capture formaldehyde. VERIFIED against NIOSH npgd0293: formaldehyde is a carcinogen (Ca) and the Pocket Guide itself lists the air-purifying gas-mask canister for ESCAPE ONLY (APF 50), with SCBA/SAR required at any detectable concentration. Routine APR use is an OSHA 1910.1048 provision, which permits a NIOSH-approved formaldehyde cartridge within its concentration table but mandates a NIOSH-approved end-of-service-life indicator (ESLI) OR a strict change-out schedule. Standard OV carbon does NOT reliably retain formaldehyde (migration/early breakthrough); a formaldehyde-approved cartridge is required. Poor warning at/below the PEL (odor threshold ~1 ppm); no dedicated ANSI K1 color, sold as a special/olive multi cartridge. You must establish a change-out schedule; never rely on taste or smell. See the cartridge & filter guide.

Calculator for Formaldehyde

Inputs

Formaldehyde exposure

Unit
ppm

This is the measured airborne level from air monitoring / an exposure assessment by a qualified person — not a guess. No sampling data yet? See how to get an exposure concentration.

ppm

Presets fill the OSHA PEL. Many IH programs use the most protective of the OSHA PEL, NIOSH REL, or ACGIH TLV — enter whichever limit you use and the calculator applies it.

ppm

Enter molecular weight to convert values when you switch between ppm and mg/m³.

Result

Enter a concentration and an exposure limit to see the compliant respirators and their Maximum Use Concentration.

Hazard ratio = concentration ÷ OEL · Minimum APF must meet or exceed it · MUC = APF × OEL (capped at IDLH). Source: OSHA 29 CFR 1910.134(d)(3)(i)(A), Table 1 — Assigned Protection Factors. Last verified 2026-07-16.

Maximum use concentration for Formaldehyde by respirator

MUC = APF × the OSHA PEL (0.75 ppm), capped at the IDLH (20 ppm). Use this as a reference for the highest concentration each respirator class may be used at.

RespiratorAPFMUC (ppm)
Air-Purifying Respirator · Quarter mask53.75
Air-Purifying Respirator · Half mask107.5
Supplied-Air Respirator (Airline) · Half mask · Demand107.5
Self-Contained Breathing Apparatus · Half mask · Demand107.5
Powered Air-Purifying Respirator · Helmet / hood2518.75
Powered Air-Purifying Respirator · Loose-fitting facepiece2518.75
Supplied-Air Respirator (Airline) · Helmet / hood · Continuous flow2518.75
Supplied-Air Respirator (Airline) · Loose-fitting facepiece · Continuous flow2518.75
Air-Purifying Respirator · Full facepiece5020IDLH
Powered Air-Purifying Respirator · Half mask5020IDLH
Supplied-Air Respirator (Airline) · Full facepiece · Demand5020IDLH
Supplied-Air Respirator (Airline) · Half mask · Continuous flow5020IDLH
Supplied-Air Respirator (Airline) · Half mask · Pressure-demand / positive-pressure5020IDLH
Self-Contained Breathing Apparatus · Full facepiece · Demand5020IDLH
Powered Air-Purifying Respirator · Full facepiece1,00020IDLH
Supplied-Air Respirator (Airline) · Full facepiece · Continuous flow1,00020IDLH
Supplied-Air Respirator (Airline) · Full facepiece · Pressure-demand / positive-pressure1,00020IDLH
Self-Contained Breathing Apparatus · Full facepiece · Pressure-demand / positive-pressure10,00020IDLH

Notes

Verified via NIOSH IDLH page + NPG search data (live NPG card fetch was 403 — re-verify card directly). OSHA 1910.1048: TWA 0.75 ppm, STEL 2 ppm, action level 0.5 ppm. NIOSH REL Ca: TWA 0.016 ppm with 15-min Ceiling 0.1 ppm. IDLH Ca [20 ppm]. Conversion 1 ppm = 1.23 mg/m3; MW 30.0.

Sources

Data confidence: high. Values are cited from OSHA and NIOSH but should be verified against the current source and a qualified professional before use. See how this works.

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