Drums and containers requirements

No — you must not pressurize shipping drums or containers to force out contents. The rule plainly states that 1915.173(a) prohibits pressurizing shipping drums and containers to remove their contents.

• Use approved pumps, siphons, gravity transfer, or manufacturer-recommended dispensing equipment instead of applying pressure.
• If the drum contains hazardous materials or residues, have a competent person evaluate safe transfer methods before work begins; see the OSHA letter on the role of the competent person in shipyards for guidance on who may make that determination.

Yes — temporarily assembled pressurized piping systems carrying hazardous liquids or gases must have a relief valve and a bypass to prevent rupture and escape. The standard requires a relief valve and by-pass for such systems as stated in 1915.173(b).

• "Relief valve" means a device sized and set to prevent system pressure from rising above safe limits; the bypass provides an alternate path so pressure can be relieved without rupturing equipment.
• Treat flexible hoses, temporary transfer lines, and improvised piping as “temporarily assembled” for purposes of the rule and provide the required devices.
• Have a competent person specify setpoints and installation details; see OSHA’s guidance on the role of a competent person in shipyards.

No — you may not store or use pressure vessels, drums, or containers with toxic or flammable liquids or gases where they are subject to open flame, hot metal, or other artificial heat. This prohibition is explicit in 1915.173(c).

• Keep such containers in cool locations away from welding, cutting, furnaces, steam lines, heaters, and other heat sources.
• If heating the contents is required for a process, use equipment specifically designed and permitted for heating hazardous liquids (e.g., approved heated tanks with controls), and have a competent person evaluate the hazards and controls (see the competent person letter).

You must erect barriers or guards unless those 30-gallon-or-larger drums or vessels are placed in an out-of-the-way area where they will not be subject to physical injury from outside sources. 1915.173(d) requires protection from physical damage.

• Examples of barriers: bollards, steel cages, guardrails, or secure enclosures that prevent vehicular or equipment impact.
• "Out-of-the-way" is a site-specific determination — the employer or a competent person should assess whether the location reasonably prevents accidental physical contact (see OSHA’s competent person guidance).

You must provide dikes or pans that enclose a volume equal to at least 35 percent of the total volume of the containers. 1915.173(e) sets this requirement.

• Calculation example: Two 55-gallon drums = 110 gallons total; 35% of 110 gal = 38.5 gallons required containment capacity.
• Containment may be individual (each drum in a pan) or collective (a sump or dike around multiple drums) as long as the enclosure volume meets the 35% requirement and prevents spilled liquid from escaping the area.
• For liquids that are denser than water or that react, consult a competent person to select compatible containment materials (see competent person guidance).

Yes — you must provide fire extinguishers that are adequate in number and suitable for the hazard in the immediate area where flammable liquids or gases are stored or used. 1915.173(f) requires extinguishers be ready for use at all times.

• For flammable liquids and gases, select extinguishers rated for Class B hazards (flammable liquids and gases); include Class C-rated extinguishers where electrical hazards exist.
• Place extinguishers so employees can reach them quickly from the storage or use area; ensure they are inspected, tagged, and maintained per employer procedures.
• If you need help matching extinguisher type and placement to the hazard, have a competent person perform the assessment (see competent person guidance).

Yes — drums that have residues of flammable or toxic liquids must be handled under the same safety considerations as full containers if the residues present a hazard. The standard's protections for storage, heating, and handling apply to containers that contain hazardous liquids or gases as written in 1915.173.

• Before designating a drum as non-hazardous, clean and decontaminate it per accepted procedures and the material safety data sheet (SDS).
• If there is any doubt, treat the container as hazardous and follow requirements for containment, guarding, heating restrictions, and fire protection.
• A qualified or competent person should evaluate whether residues create a hazard and specify controls; see OSHA’s letter on the competent person in shipyards for how that determination may be made.

The relief valve and bypass must be sized and arranged to prevent system pressure from rising to a level that could rupture the temporary piping or let hazardous material escape. 1915.173(b) requires both devices but does not prescribe exact specifications — those must be chosen to match the system.

• Relief valve: set below the maximum allowable working pressure of the weakest component and installed to relieve pressure safely to a closed collection or safe area.
• Bypass: provides an alternate flow path so pressure can be routed away from vulnerable parts (e.g., back to a tank or to a safe containment).
• Have a competent person select relief valve setpoints, sizing, and bypass routing based on system pressure, fluid properties, and practical site conditions (see OSHA’s competent person guidance).

You may provide containment for the group of containers as long as the dike or pan encloses a volume equal to at least 35 percent of the total volume of all the containers. 1915.173(e) specifies the 35% rule against the total volume.

• Example: Three 55-gallon drums total 165 gallons; required containment = 0.35 × 165 = 57.75 gallons.
• The containment must be compatible with the stored liquid and prevent escape; collective containment (sumps or diked areas) is acceptable if it meets the capacity requirement.
• Where compatibility or spill routing is complex, have a competent person evaluate containment design (see competent person guidance).

Fire extinguishers must be located in the immediate area where the containers are stored or used and must be ready for use at all times, per 1915.173(f).

• "Immediate area" means employees can access an extinguisher quickly without traversing hazardous routes; placement should reflect workplace layout and potential fire scenarios.
• Ensure extinguishers are unobstructed, mounted at a visible and reachable height, and inspected monthly and serviced annually as required by your employer’s safety program.
• If you need assistance determining spacing and number, a competent person should assess hazards and extinguisher placement (see the competent person letter).

You must show that the drums are located where they will not be subject to physical injury from outside sources; if you cannot reasonably show that, barriers are required under 1915.173(d).

• Consider traffic paths, heavy equipment operations, cargo handling, and likely impact scenarios — if any present a realistic risk of contact, use barriers or guards.
• Whether a location is "out-of-the-way" is a workplace-specific judgment best made by a competent person who can recognize hazards and specify protections (see OSHA’s competent person guidance).

Not where the drum would be "subject to" artificial heat sources that create a fire hazard; 1915.173(c) prohibits storing or using drums containing flammable liquids where they are exposed to open flame, hot metal, or other artificial heat.

• If heating is necessary for a process, use equipment specifically designed and approved for heating flammable liquids (for example, closed, jacketed, electrically heated tanks with appropriate controls and safeguards), and locate that equipment where hazards are controlled.
• Have a competent person evaluate heating methods, ignition sources, and required controls before proceeding (see competent person guidance).

Yes — flexible transfer hoses and other improvised or temporary transfer lines that form a pressurized conveyance for hazardous liquids or gases fall within the scope of 1915.173(b) and must be provided with a relief valve and bypass.

• Treat any temporarily assembled hose runs, fittings, or piping used for pressurized transfer as a pressurized system requiring overpressure protection.
• Use appropriate fittings, pressure-rated hoses, and install relief and bypass devices selected by a competent person based on system pressure and fluid properties (see the OSHA competent person letter).

The rule treats containers differently by capacity: containers 30 gallons or over may need barriers or guards unless out-of-the-way per 1915.173(d), and containers 55 gallons or more must have containment that encloses at least 35 percent of the total container volume per 1915.173(e).

• For containers 30–54 gallons: evaluate location for risk of physical damage and provide barriers if not in an out-of-the-way area.
• For containers 55 gallons and up: provide secondary containment sized to at least 35% of the total volume of those containers (single or aggregated).
• Always use a competent person to assess combined risks (impact, spills, ignition) and to design protective measures (see OSHA’s competent person guidance).