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respiratorcalc

Respirator selection

Isopropyl alcohol (2-Propanol, IPA) respirator selection(CH3)2CHOH (C3H8O)

Solvent, surface disinfectant/cleaner (rubbing alcohol), electronics cleaning, pharmaceutical and cosmetic manufacturing.

OSHA PEL
400 ppm
TWA 8-hr
NIOSH REL
400 ppm
TWA 8-hr (also STEL 500 ppm)
IDLH
2,000 ppm
Molecular weight
60.1 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.

Recommended cartridge: Organic Vapor (OV) — Black band

An APR fitted with the correct cartridge is only adequate up to its MUC (below) — the cartridge must be able to capture isopropyl alcohol (2-propanol, ipa). Standard OV cartridge acceptable up to the MUC; adequate warning. Unlike methanol, IPA is adequately captured by activated carbon (NIOSH lists CCROV), though alcohols do reduce OV service life somewhat. IDLH 2000 ppm. You must establish a change-out schedule; never rely on taste or smell. See the cartridge & filter guide.

Calculator for Isopropyl alcohol (2-Propanol, IPA)

Inputs

Isopropyl alcohol (2-Propanol, IPA) 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 Isopropyl alcohol (2-Propanol, IPA) by respirator

MUC = APF × the OSHA PEL (400 ppm), capped at the IDLH (2,000 ppm). Use this as a reference for the highest concentration each respirator class may be used at.

RespiratorAPFMUC (ppm)
Air-Purifying Respirator · Quarter mask52,000
Air-Purifying Respirator · Half mask102,000IDLH
Supplied-Air Respirator (Airline) · Half mask · Demand102,000IDLH
Self-Contained Breathing Apparatus · Half mask · Demand102,000IDLH
Powered Air-Purifying Respirator · Helmet / hood252,000IDLH
Powered Air-Purifying Respirator · Loose-fitting facepiece252,000IDLH
Supplied-Air Respirator (Airline) · Helmet / hood · Continuous flow252,000IDLH
Supplied-Air Respirator (Airline) · Loose-fitting facepiece · Continuous flow252,000IDLH
Air-Purifying Respirator · Full facepiece502,000IDLH
Powered Air-Purifying Respirator · Half mask502,000IDLH
Supplied-Air Respirator (Airline) · Full facepiece · Demand502,000IDLH
Supplied-Air Respirator (Airline) · Half mask · Continuous flow502,000IDLH
Supplied-Air Respirator (Airline) · Half mask · Pressure-demand / positive-pressure502,000IDLH
Self-Contained Breathing Apparatus · Full facepiece · Demand502,000IDLH
Powered Air-Purifying Respirator · Full facepiece1,0002,000IDLH
Supplied-Air Respirator (Airline) · Full facepiece · Continuous flow1,0002,000IDLH
Supplied-Air Respirator (Airline) · Full facepiece · Pressure-demand / positive-pressure1,0002,000IDLH
Self-Contained Breathing Apparatus · Full facepiece · Pressure-demand / positive-pressure10,0002,000IDLH

Notes

NIOSH REL TWA 400 ppm (980 mg/m3) AND STEL 500 ppm (1225 mg/m3). OSHA PEL TWA 400 ppm (980 mg/m3). IDLH 2,000 ppm [10% LEL]. Conversion 1 ppm = 2.46 mg/m3; MW 60.1.

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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