1926.1101(g)(5)(i): Negative Pressure Enclosures for Asbestos
Negative pressure enclosures may be used where the work area allows. They must keep at least 4 air changes per hour, at least -0.02 column inches of water pressure differential shown by manometer, stay under negative pressure throughout use, and direct air away from workers toward HEPA filtration. Each shift, the enclosure must be inspected, smoke-tested and sealed, and electrical circuits deactivated unless GFCI protected.
Key takeaways
- 1926.1101(g)(5)(i) is part of OSHA's construction standards (29 CFR Part 1926, Subpart Z).
- OSHA cited it 15 times in the last 3 years, in 15 inspections, with $16,000 in current penalties.
- Most citations: MI (12), 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) is one requirement inside 1926.1101 Asbestos, an OSHA construction standard (Part 1926, Subpart Z). It includes 2 sub-paragraphs. 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
(i) Negative Pressure Enclosure (NPE) systems: NPE systems may be used where the configuration of the work area does not make the erection of the enclosure infeasible, with the following specifications and work practices. 15 citations
(A) Specifications: Open (g)(5)(i)(a) 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.
(B) Work Practices: 2 citations
(1) Before beginning work within the enclosure and at the beginning of each shift, the NPE shall be inspected for breaches and smoke-tested for leaks, and any leaks sealed.
(2) Electrical circuits in the enclosure shall be deactivated, unless equipped with ground-fault circuit interrupters.
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 | 8 |
| 2025 | 4 |
| 2026 | 2 |
Top states: MI (12), VA (1), TX (1), MA (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), plus alerts when this rule changes. Free.
OSHA interpretation letters
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)(8)(iii) 15 citations
- 1926.1101(g)(1)(iii) 13 citations
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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 differential is required?
A minimum of -0.02 column inches of water relative to outside pressure, shown by manometric measurements.
When must the NPE be smoke-tested?
Before beginning work within the enclosure and at the beginning of each shift.
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.