Ventilation in shipyard welding

Mechanical ventilation must be either a general mechanical ventilation system or a local exhaust system.

• The rule states that "Mechanical ventilation shall consist of either general mechanical ventilation systems or local exhaust systems" 1915.51(b)(1)(i).
• Use general ventilation when you need to dilute and remove fumes from a larger area; use local exhaust to capture fumes at the source (for example, a movable hood placed near the arc). See 1915.51(b)(1)(ii) and 1915.51(b)(1)(iii).

General mechanical ventilation is sufficient only if it provides enough air changes to keep welding fumes and smoke in the breathing zone within safe limits.

• The standard requires that "General mechanical ventilation shall be of sufficient capacity and so arranged as to produce the number of air changes necessary to maintain welding fumes and smoke within safe limits" 1915.51(b)(1)(ii).
• Practically, this means you must evaluate air change rates and worker exposures (for example by monitoring or competent-person judgment) and increase ventilation or provide respiratory protection if contaminants build up; see the performance approach in 1915.51(f)(1).

A local exhaust hood must be placed as close to the work as practicable so it can capture fumes at the source.

• The standard specifies "Local exhaust ventilation shall consist of freely movable hoods intended to be placed by the welder or burner as close as practicable to the work" 1915.51(b)(1)(iii).
• In practice, position the hood within inches to a foot of the arc where possible, maintain hood mobility so the welder can work and capture fumes, and adjust hood placement if capture is inadequate (use a competent person’s judgment when necessary). See 29 CFR Part 1915 for broader shipyard requirements.

Contaminated air must be discharged to the open air or otherwise away from any intake air source so it won't be drawn back into the work area.

• The regulation states: "Contaminated air exhausted from a working space shall be discharged into the open air or otherwise clear of the source of intake air" 1915.51(b)(1)(iv).
• Practically, route exhaust stacks so plume does not flow toward fresh-air intakes or other working areas; avoid recirculating exhaust into the building unless it is properly cleaned and proven safe.

All air used to replace exhausted air must be clean and breathable.

• The rule requires that "All air replacing that withdrawn shall be clean and respirable" 1915.51(b)(1)(v).
• Make sure make-up air is drawn from a clean source (not from contaminated compartments or exhaust plumes) and that intake locations are sited to avoid contamination from nearby operations.

No—oxygen must not be used for ventilation, comfort cooling, blowing dust or dirt from clothing, or for cleaning the work area.

• The standard explicitly states "Oxygen shall not be used for ventilation purposes, comfort cooling, blowing dust or dirt from clothing, or for cleaning the work area" 1915.51(b)(1)(vi).
• Using oxygen in these ways is unsafe because elevated oxygen concentrations increase fire and explosion risks; use compressed air or mechanical ventilation systems designed for the purpose instead.

General ventilation meeting paragraph (b) is required for confined-space welding except where paragraphs (c)(3) or (d)(2) apply; if ventilation would block access, employees must be protected with air-line respirators and monitored by an outside attendant.

• The regulation says that "either general ventilation meeting the requirements of paragraph (b) of this section shall be provided whenever welding, cutting or heating is performed in a confined space" except as provided in (c)(3) and (d)(2) 1915.51(c)(1).
• If ventilation cannot be obtained without blocking access, then employees in the confined space must be protected by air line respirators in accordance with 1915.154, and an employee outside must maintain communication and assist in emergencies 1915.51(c)(3).
• Also ensure means of access and duct arrangement comply with 1915.51(c)(2) and 1915.76(b).

Welding, cutting, or heating involving zinc-bearing metals, lead-base metals, cadmium-bearing filler materials, and chromium-bearing metals or coatings require either general mechanical or local exhaust ventilation.

• The rule lists these metals and materials: zinc-bearing base or filler metals or zinc coatings, lead base metals, cadmium-bearing filler materials, and chromium-bearing metals or coatings and requires ventilation meeting paragraph (b) 1915.51(d)(1).
• For these materials, provide effective ventilation to control fumes at the source or use required respiratory protection when ventilation is not feasible.

For certain toxic metals, employers must use local exhaust ventilation or, if not provided, protect employees with air-line respirators; beryllium work requires both local exhaust ventilation and air-line respirators.

• The standard says welding, cutting or heating involving metals containing lead (other than as an impurity), cadmium-bearing or cadmium-coated base metals, and metals coated with mercury-bearing metals shall be performed with local exhaust ventilation meeting paragraph (b) or employees shall be protected by air line respirators per 1915.154 1915.51(d)(2)(i)-(iii).
• For beryllium-containing base or filler metals, because of high toxicity the standard requires both local exhaust ventilation and air line respirators 1915.51(d)(2)(iv).
• See also OSHA’s interim enforcement guidance for the 2020 beryllium standards which provides additional compliance context for beryllium in shipyards 2020 Beryllium Standards Guidance.

Employees performing such operations in the open air must be protected by filter-type respirators, except work on beryllium-containing metals requires air-line respirators.

• The standard specifies: "Employees performing such operations in the open air shall be protected by filter type respirators, and employees performing such operations on beryllium-containing base or filler metals shall be protected by air line respirators, in accordance with the requirements of 1915.154" 1915.51(d)(3).
• For beryllium, follow the additional guidance in OSHA’s 2021 interim enforcement memo for the 2020 beryllium standards 2020 Beryllium Standards Guidance.

Other employees exposed to the same atmosphere must be protected in the same manner as the welder or burner.

• The regulation states "Other employees exposed to the same atmosphere as the welders or burners shall be protected in the same manner as the welder or burner" 1915.51(d)(4).
• That means if welders require local exhaust or respirators for the operation, nearby workers must receive equivalent controls or respiratory protection.

Special precautions include keeping chlorinated solvents at least 200 feet from the arc, ensuring solvent-prepared surfaces are dry before welding, providing filter-lens eye protection for unshielded helpers and workers, and fully covering skin to prevent UV burns.

• The standard requires keeping chlorinated solvents at least 200 feet from the exposed arc and that surfaces prepared with chlorinated solvents be thoroughly dry before welding 1915.51(e)(1)(i).
• It also requires that helpers and other unshielded employees be protected by filter lenses meeting 1915.153 and that skin be completely covered to prevent UV damage 1915.51(e)(1)(ii)-(iii).
• For further explanation of what qualifies as ‘‘potentially injurious light radiation’’ and appropriate eye protection, see OSHA’s letter on shipyard eye and face protection Shipyard eye and face protection.

When inert-gas metal-arc welding is performed on stainless steel, employers must meet the requirements of paragraph (d)(2) to protect against dangerous concentrations of nitrogen dioxide.

• The standard specifically states: "When inert-gas metal-arc welding is being performed on stainless steel, the requirements of paragraph (d)(2) of this section shall be met to protect against dangerous concentrations of nitrogen dioxide" 1915.51(e)(1)(iv).
• That means provide appropriate local exhaust ventilation or use air-line respirators as required by 1915.51(d)(2).

No—welding, cutting, and heating not involving the specific hazardous conditions named in (c), (d), or (e) may normally be done without mechanical ventilation or respirators, but ventilation or respiratory protection must be provided when unusual conditions create an unsafe accumulation of contaminants.

• The standard explains: "...may normally be done without mechanical ventilation or respiratory protective equipment, but where, because of unusual physical or atmospheric conditions, an unsafe accumulation of contaminants exists, suitable mechanical ventilation or respiratory protective equipment shall be provided" 1915.51(f)(1).
• This is a performance-based requirement: evaluate conditions and provide controls when exposures are unsafe.

Welders and employees performing any type of welding, cutting, or heating must use suitable eye protective equipment that meets the shipyard eye-and-face protection standard, 1915.153.

• The welding ventilation rule states "Employees performing any type of welding, cutting or heating shall be protected by suitable eye protective equipment in accordance with the requirements of 1915.153" 1915.51(f)(2).
• See the detailed device criteria and filter lens requirements in 1915.153 and OSHA’s interpretation on shipyard eye protection Shipyard eye and face protection.

Means of access must be provided to the confined space and ventilation ducts must be arranged in accordance with the ducting and access rules in 1915.76(b)(1) and (b)(2).

• The ventilation rule states: "The means of access shall be provided to a confined space and ventilation ducts to this space shall be arranged in accordance with 1915.76(b)(1) and (2)" 1915.51(c)(2).
• Follow 1915.76(b) for detailed requirements on duct routing, secure attachment, and keeping access clear so workers can enter, exit, and be rescued if needed.

No—contaminated exhaust must not be recirculated into the work area unless it is discharged into the open air or otherwise clear of intake air; replacement air must be clean and respirable.

• The standard requires contaminated air "shall be discharged into the open air or otherwise clear of the source of intake air" 1915.51(b)(1)(iv) and that "All air replacing that withdrawn shall be clean and respirable" 1915.51(b)(1)(v).
• If you plan to recirculate air, you must first ensure it is adequately cleaned to respirable standards and intake locations are protected from contamination.

A competent person employed by the employer may recognize and evaluate exposures and specify necessary protection when no OSHA PEL exists.

• OSHA’s shipyard rules define the competent person and state that for subparts including welding, the competent person must be capable of specifying necessary protection; see the competent person definition in Part 1915 and the interpretations in OSHA’s letter on competent persons Competent person requirements in shipyards.
• In practice, the competent person may use other occupational exposure limits, monitoring, and professional judgment to select ventilation, respirators, or other controls to ensure worker safety 29 CFR Part 1915.

Employers must remove residues and cargoes of metallic ores of toxic significance from the area or protect them from the heat before beginning welding, cutting, or heating.

• The rule requires: "Residues and cargoes of metallic ores of toxic significance shall be removed from the area or protected from the heat before ship repair work which involves welding, cutting or heating is begun" 1915.51(g)(1).
• Practically, that means clean the work area or isolate/cover residues so heating will not vaporize toxic materials into the breathing zone.

The standard requires freely movable hoods intended to be placed by the welder as close as practicable, but fixed hoods may be used to supplement control if they provide equivalent capture.

• The regulation specifies "Local exhaust ventilation shall consist of freely movable hoods intended to be placed by the welder or burner as close as practicable to the work" 1915.51(b)(1)(iii).
• If fixed hoods are used, they must be designed and positioned so they achieve the same source capture effectiveness as movable hoods; otherwise provide movable capture or additional respiratory protection.