How OSHA Table 1 works (the silica "shortcut")
29 CFR 1926.1153 gives construction employers two ways to comply for respirable crystalline silica. The first — and by far the easier — is Table 1. Table 1 lists 18 common construction tasks and, for each, the exact engineering controls, work practices, and minimum respirator you must use. If you fully and properly follow the Table 1 entry for a task, you are relieved of the paragraph (d) exposure assessment — you do not have to do air monitoring for that task (29 CFR 1926.1153(c)(1)).
The catch is the word fully. The relief only applies if you implement every specified control and provide at least the listed respirator for your conditions. The required respirator depends on two things many crews get wrong: location (outdoors vs indoors/enclosed) and duration (4 hours/shift or less vs more than 4 hours/shift). If you skip a control or under-spec the respirator, you fall out of Table 1 and must use the alternative exposure-control method under 29 CFR 1926.1153(d) — which means assessing each employee's exposure with objective data or air sampling.
Full Table 1 respirator matrix (all 18 tasks)
Minimum Assigned Protection Factor (APF) for each task, by location and duration, transcribed from Table 1 to paragraph (c) of 29 CFR 1926.1153. "None" means no respirator is required when the listed controls are used; "N/A" means Table 1 limits that task to outdoor work, so there is no indoor entry.
| Task (Table 1 entry) | Outdoors | Indoors / enclosed | ||
|---|---|---|---|---|
| ≤ 4 hr | > 4 hr | ≤ 4 hr | > 4 hr | |
| (i) Stationary masonry saw | None | None | None | None |
| (ii) Handheld power saw (any blade diameter) | None | APF 10 | APF 10 | APF 10 |
| (iii) Handheld power saw for fiber-cement board (blade diameter ≤ 8 in, outdoors only) | None | None | N/A | N/A |
| (iv) Walk-behind saw | None | None | APF 10 | APF 10 |
| (v) Drivable saw (outdoors only) | None | None | N/A | N/A |
| (vi) Rig-mounted core saw or drill | None | None | None | None |
| (vii) Handheld and stand-mounted drills (incl. impact and rotary hammer drills) | None | None | None | None |
| (viii) Dowel drilling rigs for concrete (outdoors only) | APF 10 | APF 10 | N/A | N/A |
| (ix) Vehicle-mounted drilling rigs for rock and concrete | None | None | None | None |
| (x) Jackhammers and handheld powered chipping tools | None | APF 10 | APF 10 | APF 10 |
| (xi) Handheld grinders for mortar removal (i.e., tuckpointing) | APF 10 | APF 25 | APF 10 | APF 25 |
| (xii) Handheld grinders for uses other than mortar removal | None | None | None | APF 10 |
| (xiii) Walk-behind milling machines and floor grinders | None | None | None | None |
| (xiv) Small drivable milling machines (less than half-lane) | None | None | None | None |
| (xv) Large drivable milling machines (half-lane and larger) | None | None | None | None |
| (xvi) Crushing machines | None | None | None | None |
| (xvii) Heavy equipment / utility vehicles used to abrade or fracture silica-containing materials (e.g., hoe-ramming, rock ripping) or during demolition | None | None | None | None |
| (xviii) Heavy equipment / utility vehicles for grading and excavating (NOT demolishing, abrading, or fracturing) | None | None | None | None |
Source: Table 1 to paragraph (c) of 29 CFR 1926.1153, verified 2026-06-26 against the OSHA.gov standard text and the eCFR.
What "APF 10" and "APF 25" actually mean
Table 1 specifies a minimum Assigned Protection Factor (APF), not a specific brand or model. APF is the workplace level of respiratory protection a properly functioning, correctly worn respirator is expected to provide (29 CFR 1910.134(d)): an APF 10 respirator is expected to reduce the wearer's exposure to about one-tenth of the airborne concentration, and an APF 25 to about one twenty-fifth. Any NIOSH-approved respirator with at least the listed APF, used inside a written 1910.134 program (medical evaluation, fit testing, training), satisfies the requirement.
| Table 1 requirement | Typical respirators that meet it | Fit test required? |
|---|---|---|
| None | No respirator required when the listed controls are used fully and properly. | No |
| APF 10 | N95 (or better) filtering facepiece, or an elastomeric half-mask. | Yes — annual fit test + medical eval first. |
| APF 25 | Loose-fitting PAPR, or a supplied-air respirator (loose-fitting / half-mask facepiece). | Loose-fitting PAPR: no fit test; tight-fitting: yes. |
Need to pick the right fit-test method for the respirator you choose? Use the respirator fit-test method selector.
Worked examples
1 — Handheld power saw, concrete, outdoors, 6 hours. This is entry (ii). The control is an integrated water-delivery saw. Outdoors for 4 hours or less, no respirator is required — but because the crew runs the saw more than 4 hours, Table 1 requires a minimum APF 10 respirator (e.g. an N95 half-mask) in a 1910.134 program. The frequent mistake is to assume outdoor cutting never needs a respirator; over 4 hours it does.
2 — Tuckpointing grinder, mortar removal, indoors, 5 hours. This is entry (xi). The control is a shroud + dust-collection system delivering ≥25 cfm per inch of wheel diameter with a HEPA filter. Tuckpointing always requires a respirator: APF 10 for 4 hours or less, and because this job exceeds 4 hours, a minimum APF 25 (e.g. a loose-fitting PAPR or supplied-air respirator). Indoors makes no difference for entry (xi) — the requirement is the same indoors and outdoors. Because a respirator is required and this crew tuckpoints most days, watch the 30-days/year threshold that triggers medical surveillance under 29 CFR 1926.1153(h)(1)(i).
What to do next
- Build the written exposure control plan. Required on the Table 1 route too (29 CFR 1926.1153(g)): list each silica task, the controls, the respirators, and housekeeping, and name a competent person who inspects the site frequently and regularly.
- Stand up a respiratory-protection program per 29 CFR 1910.134 — medical evaluation, fit testing, and training — before anyone wears the required respirator.
- Track 30 days/year of respirator use per employee. Hit 30 days and you must offer medical surveillance (construction trigger), not the general-industry action-level test.
- If a task isn't on Table 1 (or you can't fully follow it), estimate exposure and plan air monitoring with the silica exposure calculator.
Frequently asked questions
What respirator does OSHA require for a handheld power saw used outdoors for more than 4 hours?
Under Table 1 of 29 CFR 1926.1153, a handheld power saw (entry (ii)) used OUTDOORS requires no respirator for 4 hours/shift or less, but a minimum APF 10 respirator when used outdoors for MORE than 4 hours per shift — provided you use the integrated-water control. Used indoors or in an enclosed area, entry (ii) requires APF 10 for any duration. (A common error is to assume outdoor work over 4 hours needs no respirator — Table 1 says APF 10.)
What respirator does OSHA require for a handheld grinder cutting concrete indoors for more than 4 hours?
Handheld grinders for uses other than mortar removal (entry (xii)) require a minimum APF 10 respirator when used indoors or in an enclosed area for more than 4 hours per shift, with the integrated-water or HEPA dust-collection control. For 4 hours or less indoors (and for all outdoor durations) no respirator is required. Mortar-removal/tuckpointing grinding (entry (xi)) is different — it always requires a respirator: APF 10 for 4 hours or less, APF 25 for more than 4 hours.
Does following Table 1 mean I do not have to do air monitoring for silica?
Yes. 29 CFR 1926.1153(c)(1) lets you fully and properly implement the engineering controls, work practices, and respiratory protection specified in Table 1 for a task; if you do, you are relieved of the paragraph (d) exposure-assessment (air monitoring) obligation for that task. If you do not fully follow Table 1, you must use the alternative exposure-control method under (d), which requires assessing each employee's exposure.
When does the silica standard require medical surveillance in construction?
In construction (29 CFR 1926.1153(h)(1)(i)), you must make medical surveillance available to any employee who is required to use a respirator under the standard for 30 or more days per year. This differs from general industry (29 CFR 1910.1053), where the trigger is exposure at or above the action level for 30 or more days per year. Do not confuse the two.
What are the silica PEL and action level?
The permissible exposure limit (PEL) for respirable crystalline silica is 50 µg/m³ and the action level is 25 µg/m³, both as an 8-hour time-weighted average (29 CFR 1926.1153). These limits apply whether you use the Table 1 route or the alternative exposure-control method.
Do I still need a written plan if I follow Table 1?
Yes. A written exposure control plan is required under 29 CFR 1926.1153(g) regardless of whether you use Table 1 or the alternative method. It must describe the silica-generating tasks, the engineering controls and work practices used, the respiratory protection used, and housekeeping measures, and a competent person must make frequent and regular inspections of the job site.
What does APF 10 or APF 25 mean for a silica respirator?
APF is the Assigned Protection Factor — the level of protection a properly selected, fit-tested, and correctly worn respirator is expected to provide (29 CFR 1910.134(d)). An APF 10 respirator (e.g. an N95 or other half-mask) is expected to keep the wearer's exposure to about one-tenth of the airborne concentration; an APF 25 respirator (e.g. a loose-fitting PAPR or supplied-air respirator) to about one twenty-fifth. Table 1 lists the MINIMUM APF, so any NIOSH-approved respirator with at least that APF, used in a 1910.134 program, is acceptable.
What if my exact tool or task is not listed in Table 1?
Table 1 covers 18 specific construction tasks. If your task is not one of them — or you cannot fully and properly implement the specified controls and respirator — you cannot use the Table 1 route for it. You must use the alternative exposure-control method under 29 CFR 1926.1153(d): assess each employee's exposure using objective data or air sampling, keep exposures at or below the 50 µg/m³ PEL, and provide respirators selected for the measured exposure. The same applies to an indoor version of a task that Table 1 limits to outdoor work (entries (iii), (v), and (viii)).
How many tasks are listed in Table 1, and are any limited to outdoor work?
Table 1 to paragraph (c) of 29 CFR 1926.1153 lists 18 specified construction tasks, entries (i) through (xviii). Three entries are limited to outdoor work in Table 1: (iii) handheld saws for fiber-cement board, (v) drivable saws, and (viii) dowel drilling rigs for concrete. For an indoor version of one of those tasks you cannot use the Table 1 entry — you must use the (d) alternative exposure-control method with air monitoring. The remaining 15 tasks apply indoors and outdoors, with the required respirator varying by location and by the ≤4 hr vs >4 hr/shift split.
Sources & verification
- 29 CFR 1926.1153 — Respirable Crystalline Silica (OSHA.gov), Table 1 to paragraph (c)
- eCFR — 29 CFR 1926.1153 (current text)
Table 1 figures verified 2026-06-26. This selector is a planning/reference guide, not legal advice, and is not a substitute for a site-specific exposure control plan or the air monitoring required when you do not fully follow Table 1. State-Plan states may adopt equivalent or more protective requirements.
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