Flammable liquid precautions

Yes. Employers must use the precautions in 1915.36(a) whenever liquid solvents, paint removers, paints or vehicles (except those covered by 1915.35(b) ) can produce a flammable atmosphere under the conditions of use.

• Make the determination by looking at the materials in use, the work process, and environmental conditions (heating, confined spaces, poor ventilation).
• If the material is covered by 1915.35(b), these specific 1915.36 precautions may not apply; check that subsection first.

(See 1915.36(a) and 1915.35(b).)

No. 1915.36(a)(1) requires that smoking, open flames, arcs and spark-producing equipment be prohibited in areas where the listed liquids can produce a flammable atmosphere.

• Prohibit ignition sources in the work area and post clear signage and barriers.
• Include hot work controls (welding, cutting) and enforce hot-work permits or alternative safeguards when operations cannot be fully isolated.

(See 1915.36(a)(1) and the general application in 1915.36(a).)

You must provide ventilation that keeps vapor concentrations below ten percent of the lower explosive limit (LEL) and make frequent tests by a competent person, per 1915.36(a)(2).

• Ventilation: design local or general ventilation so measured vapor levels are under 10% LEL during normal operations.
• Testing: have a competent person perform frequent checks with appropriate instruments to verify the vapor level stays below 10% LEL.
• Documentation: keep records of testing frequency and results where your safety program requires it.

(See 1915.36(a)(2) and the OSHA Letter of Interpretation explaining the role of the competent person in shipyard atmospheres: https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18.)

A competent person must perform the vapor concentration tests, and that person is someone capable of recognizing and evaluating hazardous atmospheres and specifying necessary protections, as explained in OSHA's shipyard competent-person guidance and the Part 1915 definitions (see https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18 and the Part 1915 definitions cited therein).

• The competent person should be trained to use and interpret the monitoring instruments being used (e.g., combustible-gas indicators calibrated for LEL).
• The competent person may also set testing frequency based on operations, ventilation effectiveness, and observed hazard.
• Employers must ensure the competent person can ‘‘specify the necessary protection and precautions’’ under 29 CFR Part 1915 definitions discussed in the OSHA interpretation.

(See 1915.36(a)(2) and OSHA’s competent person guidance at https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18.)

It means you must keep vapor concentrations measured in air below 10% of the chemical’s LEL (the concentration below which a flammable vapor/air mixture will not ignite), as required by 1915.36(a)(2).

• Find the LEL for the specific solvent or liquid in its Safety Data Sheet (SDS) or reliable technical data.
• Calculate 10% of that LEL (for example, if LEL = 1.0% by volume, the control limit = 0.10% by volume).
• Use properly calibrated combustible-gas detectors or gas monitors to measure the workplace atmosphere at representative locations.

(See 1915.36(a)(2).)

You must keep scrapings and rags soaked with these materials in a covered metal container, as required by 1915.36(a)(3).

• Use UL- or FM-listed metal waste cans with self-closing lids where practical.
• Empty containers regularly and follow your waste-disposal rules; do not allow rags to accumulate.
• If laundering rags, follow a written procedure that prevents ignition during storage and transport to the laundry.

(See 1915.36(a)(3).)

Only explosion-proof lights approved for Class I, Group D atmospheres by Underwriters Laboratories, or lights approved by MSHA or the U.S. Coast Guard, may be used in those areas, per 1915.36(a)(4).

• Use fixtures and portable lamps that are explicitly listed for Class I, Group D service (hydrocarbon vapors).
• For temporary lighting, select lamps with the proper explosion-proof rating and ensure seals and housings are intact.
• Verify equipment approval markings and keep documentation of approvals as part of your safety files.

(See 1915.36(a)(4).)

The competent person must inspect that insulation is in excellent condition (no cracks or worn spots), that there are no connections within 50 feet of the operation, that lines are not overloaded, and that cables are suspended with sufficient slack to prevent undue stress or chafing, per 1915.36(a)(5).

• Inspect cable jackets, strain reliefs, plugs, and junction boxes for damage and wear.
• Ensure connections and splices are located beyond 50 feet from the work area or are enclosed and rated for the hazard.
• Confirm load ratings so circuits are not overloaded; document inspections and corrections.
• The OSHA interpretation of competent person duties for shipyard atmospheres clarifies that the competent person must be able to recognize hazards and specify protections (https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18).

(See 1915.36(a)(5) and OSHA’s competent person guidance at https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18.)

It means you must avoid electrical connections (splices, plugs, junctions) within 50 feet of the operation unless those connections are made in a way that does not create an ignition hazard (for example, explosion-proof enclosures). This requirement is in 1915.36(a)(5).

• If you must place electrical equipment closer, use equipment and enclosures rated for Class I, Group D atmospheres and follow manufacturer and approval requirements.
• Prefer remote power supplies or hardwired explosion-proof fixtures to avoid in-area connections.
• Have the competent person evaluate and document any deviation and the protective measures implemented.

(See 1915.36(a)(5) and OSHA competent person guidance at https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18.)

Suitable fire extinguishing equipment must be immediately available and maintained in a state of readiness for instant use, as required by 1915.36(a)(6).

• Provide extinguishers appropriate to the fuel types (Class B for flammable liquids) and sized for the hazards present.
• Place extinguishers so they are within quick reach of employees and keep access unobstructed.
• Maintain extinguishers per NFPA and manufacturer instructions: regular visual checks, monthly inspections, and annual maintenance; replace or service immediately after use.

(See 1915.36(a)(6).)

A "competent person" is someone who can recognize and evaluate hazardous atmospheres or unsafe conditions and is capable of specifying the necessary protection and precautions, as described in OSHA's Part 1915 definitions and discussed in the agency's shipyard competent-person interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18.

• For the 1915.36(a)(5) inspection duties, the competent person must understand electrical hazards, cable integrity, and how to prevent ignition sources in flammable atmospheres.
• Employers are responsible for ensuring the competent person has the training, authority, and resources to carry out inspections and corrective actions.

(See 1915.36(a)(5) and OSHA’s competent person guidance at https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18.)

Use calibrated combustible-gas indicators or gas monitors designed to read percent LEL for the specific class of hydrocarbon vapors you expect; such instruments, operated by a competent person, are appropriate for verifying the 1915.36(a)(2) 10% LEL requirement.

• Select instruments with the proper sensor type for hydrocarbons (catalytic bead or infrared, as appropriate) and ensure regular calibration per manufacturer instructions.
• Take measurements at representative locations and heights (near breathing zones and near potential vapor accumulations) and after changes in work conditions.
• The competent person should interpret readings and decide corrective actions (ventilation, work stoppage) as advised in OSHA’s competent person guidance (https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18).

(See 1915.36(a)(2) and OSHA competent person letter at https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18.)

Yes. The 1915.36(a) precautions are specific to flammable liquids, but you must also comply with other applicable Part 1915 requirements (such as Subpart P Fire Protection and any hot-work rules) that apply to your operations, as noted in OSHA guidance (see https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18 discussing related Subparts).

• Integrate 1915.36(a) controls (ventilation, lighting, inspections, extinguishers) with hot-work permit systems and fire-watch procedures where welding, cutting, or other hot work occurs.
• Coordinate competent-person testing and hazard assessments required under multiple subparts of Part 1915.

(See 1915.36(a) and OSHA’s discussion of how competent persons and related subparts interrelate at https://www.osha.gov/laws-regs/standardinterpretations/2016-04-18.)

Yes. You may use LED fixtures only if they are approved and listed for Class I, Group D atmospheres (or approved by MSHA/USCG), consistent with 1915.36(a)(4).

• Check manufacturer markings and approval listings (e.g., UL listing) to confirm the fixture is rated for Class I, Group D use.
• Ensure installation meets the approval conditions (sealed enclosures, wiring methods) and is regularly inspected to maintain the explosion-proof integrity.

(See 1915.36(a)(4).)

They may be stored in covered metal containers, but you must manage them so they do not present an ignition hazard and must follow good housekeeping and local fire codes; 1915.36(a)(3) requires they be kept in covered metal containers.

• Empty and remove containers regularly to prevent spontaneous combustion and comply with your facility’s waste handling procedures.
• Follow any additional local fire-code or company rules on container capacity, labeling, and storage location.

(See 1915.36(a)(3).)