1926.1101(g)(5)(i)(A): Negative Pressure Enclosure Specifications
A negative pressure enclosure (NPE) for asbestos work may have any shape but must keep at least 4 air changes per hour and at least -0.02 column inches of water pressure difference measured by manometer, stay under negative pressure the whole time it is used, and move air away from workers toward a HEPA filter or collection device.
Key takeaways
- 1926.1101(g)(5)(i)(A) is part of OSHA's construction standards (29 CFR Part 1926, Subpart Z).
- OSHA cited it 13 times in the last 3 years, in 13 inspections, with $16,000 in current penalties.
- Most citations: MI (11), VA (1), TX (1).
- Related part: 1926.1101(g) Methods of compliance (297 citations).
- Free 5-minute toolbox talk for your crew below.
In this article
What this rule covers
29 CFR 1926.1101(g)(5)(i)(A) ("Specifications:") is one requirement inside 1926.1101 Asbestos, an OSHA construction standard (Part 1926, Subpart Z). The official text below is copied word for word from the Electronic Code of Federal Regulations (eCFR). The numbers, injury cases and training on this page show how OSHA enforces it on real job sites.
Official text
(A) Specifications: 13 citations
(1) The negative pressure enclosure (NPE) may be of any configuration,
(2) At least 4 air changes per hour shall be maintained in the NPE,
(3) A minimum of −0.02 column inches of water pressure differential, relative to outside pressure, shall be maintained within the NPE as evidenced by manometric measurements,
(4) The NPE shall be kept under negative pressure throughout the period of its use, and
(5) Air movement shall be directed away from employees performing asbestos work within the enclosure, and toward a HEPA filtration or a collection device.
Source: eCFR, text current as of 2026-10-15. Read all of 1926.1101.
Where and how often it was cited
| Year | Citations |
|---|---|
| 2023 | 1 |
| 2024 | 7 |
| 2025 | 4 |
| 2026 | 1 |
Top states: MI (11), VA (1), TX (1)
Largest penalties
| Employer | Location | Penalty for this rule |
|---|---|---|
| THERMAL SOLUTIONS, INC. | GLEN LYN, VA | $5,500 |
| TOTAL ENVIRONMENTAL SERVICES LLC | OSSINEKE, MI | $4,200 |
| DETROIT ENVIRONMENTAL SOLUTIONS, LLC | FLINT, MI | $2,100 |
| JC ENVIRONMENTAL, INC. | EL PASO, TX | $1,500 |
| ENVIRONMENTAL MANAGEMENT SPECIALISTS, INC. | BERRIEN SPRINGS, MI | $1,050 |
Free toolbox talk
A 5-minute crew talk on 1926.1101(g)(5)(i)(A), plus alerts when this rule changes. Free.
OSHA interpretation letters
None exist. OSHA has not published a letter of interpretation for 1926.1101(g)(5)(i)(A).
Related parts of this rule
- 1926.1101(g) Methods of compliance 297 citations
- 1926.1101(g)(1) 105 citations
- 1926.1101(g)(8) Additional Controls for Class II work 71 citations
- 1926.1101(g)(7) Work practices and engineering controls for Class II work 40 citations
- 1926.1101(g)(5) Specific control methods for Class I work 29 citations
- 1926.1101(g)(8)(i) 28 citations
- 1926.1101(g)(7)(i) 25 citations
- 1926.1101(g)(8)(ii) 18 citations
- 1926.1101(g)(1)(ii) 16 citations
- 1926.1101(g)(4) Class I Requirements 15 citations
- 1926.1101(g)(5)(i) 15 citations
- 1926.1101(g)(8)(iii) 15 citations
Get your crew competent
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Frequently asked questions
How many air changes are required in an NPE?
At least 4 air changes per hour.
What pressure difference is required?
A minimum of -0.02 column inches of water relative to outside, shown by manometric measurements.
Which way must the air flow?
Away from employees doing asbestos work and toward a HEPA filtration or collection device.
About this page
Sources
- 29 CFR 1926.1101 (eCFR), text current as of 2026-10-15
- U.S. Department of Labor enforcement data: OSHA inspections, citations and accident records, copied nightly; data as of 2026-10-20
3-year window. Federal OSHA only; state-plan rules are not counted. Plain-language text is a summary, not legal advice; the official text controls. Black Belt Safety is not part of OSHA or the Department of Labor.