Respirators for Confined Spaces and IDLH Atmospheres
Confined space entry, oxygen deficiency and IDLH atmospheres: the exposure limits, the OSHA and Cal/OSHA rule paragraphs as written, and the North and Dräger respirators, cartridges and filters whose own published data lists the hazard, with live prices. We sell nationwide; ships in 1–2 business days; most orders arrive in 3–7 business days.
The exposure limits
| Source | Limit |
|---|---|
| 29 CFR 1910.134(d)(2)(iii) | All oxygen-deficient atmospheres shall be considered IDLH (oxygen below 19.5 percent by volume per the definition in 1910.134(b)) |
What the federal rule says
Each entry is condensed from the paragraph cited; the paragraph itself is the rule and the link opens it.
29 CFR 1910.134(d)(2)(i): The employer shall provide the following respirators for employee use in IDLH atmospheres: a full facepiece pressure demand SCBA certified by NIOSH for a minimum service life of thirty minutes, or a combination full facepiece pressure demand supplied-air respirator (SAR) with auxiliary self-contained air supply.
29 CFR 1910.134(d)(2)(ii): Respirators provided only for escape from IDLH atmospheres shall be NIOSH-certified for escape from the atmosphere in which they will be used.
29 CFR 1910.146(b): Immediately dangerous to life or health (IDLH) means any condition that poses an immediate or delayed threat to life or that would cause irreversible adverse health effects or that would interfere with an individual's ability to escape unaided from a permit space.
29 CFR 1910.252(c)(4)(iii) (welding in confined spaces): In areas immediately hazardous to life, a full-facepiece, pressure-demand, self-contained breathing apparatus or a combination full-facepiece, pressure-demand supplied-air respirator with an auxiliary, self-contained air supply approved by NIOSH under 42 CFR part 84 must be used.
Source: 29 CFR, Occupational Safety and Health Standards, as published by OSHA (ecfr.gov / osha.gov), read Nov 2–3 2026.
California (Cal/OSHA)
Each entry is condensed from the paragraph cited; the paragraph itself is the rule and the link opens it.
Title 8 §5144(d)(2) and §5157: Cal/OSHA carries the same IDLH respirator rule in §5144(d)(2) and the permit-required confined space rules in §5157.
Source: California Code of Regulations, Title 8, as published by Cal/OSHA (dir.ca.gov), read Nov 2–3 2026.
What the makers' data lists for confined space entry, oxygen deficiency and IDLH atmospheres
The air-purifying cartridges and the continuous-flow supplied-air assemblies on this site are NIOSH approved for non-IDLH atmospheres; the North CF-SAR assemblies carry the Type C continuous-flow approval (TC-19C), and the approval label cautions state "not for use in atmospheres immediately dangerous to life or health" and "not for use in atmospheres containing less than 19.5 percent oxygen". We do not list SCBA on this site. The escape devices below (North 7900 mouthbits, the ER2000CBRN hood, Dräger PARAT hoods) are NIOSH or EN certified for escape only. Draeger-Tubes for confined-space gas testing are on the Draeger tubes hub.
North cartridges and filters whose chart entry covers it
| Part number | Item | Version | Price | |
|---|---|---|---|---|
| N75003L | North N75003L Organic Vapor and Acid Gas (OV/AG) Cartridge Organic Vapor and Acid Gas (Chlorine, Hydrogen Chloride, Sulfur Dioxide, Hydrogen Fluoride, Hydrogen Sulfide, Chlorine D; label Yellow | $16.49 | ||
| 75SCL | North 75SCL Defender Multi-Gas Vapor Cartridge Organic Vapor, Ammonia, Methylamine, Formaldehyde and Acid Gas (Chlorine, Hydrogen Chloride, Sulfur Dioxide, Hydrogen Su; label Olive | $16.99 | ||
| 7583P100L | North 7583P100L Organic Vapor and Acid Gas (OV/AG) Cartridge with P100 Filter Organic Vapor and Acid Gas (Chlorine, Hydrogen Chloride, Sulfur Dioxide, Hydrogen Fluoride, Hydrogen Sulfide, Chlorine D; label Yellow and Magenta | $26.99 | ||
| 75SCP100L | North 75SCP100L Defender Multi-Contaminant Cartridge with P100 Filter Organic Vapor, Ammonia, Methylamine, Formaldehyde and Acid Gas (Chlorine, Hydrogen Chloride, Sulfur Dioxide, Hydrogen Su; label Olive and Magenta | $30.99 |
Source: North Cartridge & Filter Reference Chart; NIOSH approval labels (PIP).
North facepieces
Source: North product sheets (PIP).
North supplied-air respirators and hoods
Source: North CF2000 and Primair product sheets (PIP).
North escape respirators
| Part number | Item | Version | Price | |
|---|---|---|---|---|
| 7902 | North 7900 Series Emergency Escape Mouthbit Respirator | Acid gas | $256.00 | |
| 7904 | North 7900 Series Emergency Escape Mouthbit Respirator | Ammonia / methylamine (silicone) | $323.00 | |
| ER2000CBRN | North ER2000CBRN CBRN Escape Hood | $346.00 |
Source: North 7900 Series and ER2000CBRN data sheets (PIP).
Dräger masks
Source: Dräger Product Catalog, Industrial Applications (DMC-107423).
Dräger PARAT escape hoods
| Part number | Item | Version | Price | |
|---|---|---|---|---|
| 3721331 | Draeger 3721331 PARAT 4920 Industrial Escape Hood, NIOSH, Soft Pack | $267.27 | ||
| R59431 | Draeger R59431 PARAT 4730 Industrial Escape Hood, Hard Case | $221.47 | ||
| R59415 | Draeger PARAT 5500 Series Fire Escape Hood | PARAT 5510 Single Pack | $274.93 | |
| 3721330 | Draeger PARAT 5500 Series Fire Escape Hood | PARAT 5520 Soft Pack | $306.87 | |
| R59435 | Draeger PARAT 5500 Series Fire Escape Hood | PARAT 5530 Hard Case | $308.88 | |
| R59445 | Draeger PARAT 5550 Fire Escape Hood with Holster | PARAT 5550 | $375.91 | |
| 3700073 | Draeger PARAT 5550 Fire Escape Hood with Holster | PARAT 5550h | $382.70 | |
| 3721329 | Draeger PARAT 7500 Series Fire and Industrial Escape Hood | PARAT 7520 Soft Pack | $366.58 | |
| R59437 | Draeger PARAT 7500 Series Fire and Industrial Escape Hood | PARAT 7530 Hard Case | $363.52 | |
| 3702150 | Draeger 3702150 PARAT 1260 Mouthpiece Escape Respirator, ABEK 10 Filter | $83.90 | ||
| 3704477 | Draeger 3704477 PARAT 3160 Half Mask Escape Respirator, Pack of 12 | $1379.40 | ||
| 3704479 | Draeger 3704479 PARAT 3260 Mouthpiece Escape Respirator, Pack of 12 | $1532.52 |
Source: Dräger PARAT product pages (draeger.com).
Assigned protection factor
| Respirator type (OSHA Table 1) | APF |
|---|---|
| Supplied-air respirator, continuous flow, half mask | 50 |
| Supplied-air respirator, continuous flow, full facepiece | 1000 |
| Supplied-air respirator, continuous flow, helmet/hood (manufacturer-tested to APF 1,000) | 1000 |
Source: OSHA 29 CFR 1910.134 Table 1 (Assigned Protection Factors). The APF applies only when the respirator is used in a program that meets the standard, including fit testing of tight-fitting facepieces (29 CFR 1910.134(f)) and a cartridge change schedule (29 CFR 1910.134(d)(3)(iii)).
Guides: half mask vs full facepiece · assigned protection factors · cartridge change schedules · P100 vs N95 vs R95 · what OSHA requires for fit testing · cleaning and storing respirators.
Respirators for Confined Spaces and IDLH Atmospheres questions
Can an air-purifying respirator be used in a confined space? Not in an IDLH or oxygen-deficient atmosphere: 29 CFR 1910.134(d)(2) requires a pressure-demand SCBA or a combination pressure-demand SAR with auxiliary air there, and the NIOSH approval labels on cartridges state they are not for use below 19.5 percent oxygen or in IDLH atmospheres.
What counts as oxygen deficient? Below 19.5 percent oxygen by volume (29 CFR 1910.134(b)); all oxygen-deficient atmospheres are IDLH under 1910.134(d)(2)(iii).