WAC 296-304-04001   Ventilation and protection in welding, cutting and heating.  (1) Mechanical ventilation requirements.

     (a) For the purposes of this section, mechanical ventilation shall meet the following requirements:

     (i) Mechanical ventilation shall consist of either general mechanical ventilation systems or local exhaust systems.

     (ii) 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.

     (iii) 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. This system shall be of sufficient capacity and so arranged as to remove fumes and smoke at the source and keep the concentration of them in the breathing zone within safe limits.

     (iv) Contaminated air exhausted from a working space shall be discharged into the open air or otherwise clear of the source of intake air.

     (v) All air replacing that withdrawn shall be clean and respirable.

     (vi) Oxygen shall not be used for ventilation purposes, comfort cooling, blowing dust or dirt from clothing, or for cleaning the work area.

     (2) Welding, cutting and heating in confined spaces.

     (a) Except as provided in WAC 296-304-04001 (2)(c) and (3)(b), either general mechanical or local exhaust ventilation meeting the requirements of (1) of this section shall be provided whenever welding, cutting or heating is performed in a confined space.

     (b) The means of access shall be provided to a confined space and ventilation ducts to this space shall be arranged in accordance with WAC 296-304-05011 (2)(a) and (b).

     (c) When sufficient ventilation cannot be obtained without blocking the means of access, employees in the confined space shall be protected by air line respirators in accordance with the requirements of chapter 296-842 WAC, and an employee on the outside of such a confined space shall be assigned to maintain communication with those working within it and to aid them in an emergency.

     (3) Welding, cutting or heating of metals of toxic significance.

     (a) Welding, cutting or heating in any enclosed spaces aboard the vessel involving the metals specified in this subsection shall be performed with either general mechanical or local exhaust ventilation meeting the requirements of (1) of this section.

     (i) Zinc-bearing base or filler metals or metals coated with zinc-bearing materials.

     (ii) Lead base metals.

     (iii) Cadmium-bearing filler materials.

     (iv) Chromium-bearing metals or metals coated with chromium-bearing materials.

     (b) Welding, cutting, or heating in any enclosed spaces aboard the vessel involving the metals specified in this subsection shall be performed with local exhaust ventilation in accordance with the requirements of (1) of this section or employees shall be protected by air line respirators in accordance with the requirements of chapter 296-842 WAC.

     (i) Metals containing lead, other than as an impurity, or metals coated with lead-bearing materials.

     (ii) Cadmium-bearing or cadmium coated base metals.

     (iii) Metals coated with mercury-bearing metals.

     (iv) Beryllium-containing base or filler metals. Because of its high toxicity, work involving beryllium shall be done with both local exhaust ventilation and air line respirators.

     (c) Employees performing such operations in the open air shall be protected by filter type respirators in accordance with the requirements of WAC 296-304-09003, except that employees performing such operations on beryllium-containing base or filler metals shall be protected by air line respirators in accordance with the requirements of chapter 296-842 WAC.

     (d) Other employees exposed to the same atmosphere as the welders or burners shall be protected in the same manner as the welder or burner.

     (4) Inert-gas metal-arc welding.

     (a) Since the inert-gas metal-arc welding process involves the production of ultraviolet radiation of intensities of 5 to 30 times that produced during shielded metal-arc welding, the decomposition of chlorinated solvents by ultraviolet rays, and the liberation of toxic fumes and gases, employees shall not be permitted to engage in, or be exposed to the process until the following special precautions have been taken:

     (i) The use of chlorinated solvents shall be kept at least two hundred feet from the exposed arc, and surfaces prepared with chlorinated solvents shall be thoroughly dry before welding is permitted on such surfaces.

     (ii) Helpers and other employees in the area not protected from the arc by screening as provided in WAC 206-304-04011(5) shall be protected by filter lenses meeting the requirements of Tables I-1A and B (see below). When two or more welders are exposed to each other's arc, filter lens goggles of a suitable type meeting the requirements of WAC 296-304-09001 (1) and (3) shall be worn under welding helmets or hand shields to protect the welder against flashes and radiant energy when either the helmet is lifted or the shield is removed.

     (iii) Welders and other employees who are exposed to radiation shall be suitably protected so that the skin is covered completely to prevent burns and other damage by ultraviolet rays. Welding helmets and hand shields shall be free of leaks and openings, and free of highly reflective surfaces.

     (iv) When inert-gas metal-arc welding is being performed on stainless steel, the requirements of (3)(b) of this section shall be met to protect against dangerous concentrations of nitrogen dioxide.

     (5) General welding, cutting and heating.

     (a) Welding, cutting and heating not involving conditions or materials described in (2), (3) or (4) of this section 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.

     (b) Employees performing any type of welding, cutting or heating shall be protected by suitable eye protective equipment in accordance with the requirements of Tables I-1A and B (see below).

     (6) Residues and cargos of metallic ores.

     Residues and cargos of metallic ores of toxic significance shall be removed from the area or protected from the heat before welding, cutting or heating is begun.


TABLE I-1A


FILTER LENSES FOR PROTECTION AGAINST

RADIANT ENERGY


OPERATIONS ELECTRODE

SIZE 1/32 IN		 ARC

CURRENT		 MINIMUM

PROTECTIVE

SHADE
Shielded metal arc welding Less than 3

3-5

5-8

More than 8		 Less than 60

60-160

160-250

250-550		 7

8

10

11
Gas metal arc welding and flux cored arc welding   Less than 60

60-160

160-250

250-550		 7

10

10

10
Gas Tungsten arc welding   Less than 50

50-150

150-500		 8

8

10
Air carbon arc cutting (Light)

(Heavy)		 Less than 500

500-1000		 10

11
Plasma arc welding   Less than 20

20-100

100-400

400-800		 6

8

10

11
Plasma arc cutting (Light)**

(Medium)**

(Heavy)**		 Less than 300

300-400

400-800		 8

9

10
Torch brazing -- -- 3
Torch soldering -- -- 2
Carbon Arc welding -- -- 14
** These values apply where the actual arc is clearly seen. Lighter filters may be used when the arc is hidden by the workplace.
TABLE I-1B


FILTER LENSES FOR PROTECTION AGAINST

RADIANT ENERGY

OPERATIONS PLATE

THICKNESS...

INCHES		 PLATE

THICKNESS...

MM		 MINIMUM*

PROTECTIVE

SHADE
Gas welding
Light

Medium

Heavy		 Under 1/8

1/8 - 1/2

Over 1/2		 Under 3.2

3.2 - 12.7

Over 12.7		 4

5

6
Oxygen cutting
Light

Medium

Heavy		 Under 1

1 - 6

Over 6		 Under 25

25 - 100

Over 150		 3

4

5
* As rule of thumb, start with a shade that is too dark to see the weld zone. Then go to a lighter shade which gives sufficient view of the weld zone without going below the minimum. In oxyfuel gas welding or cutting where the torch produces a high yellow light, it is desirable to use a filter lens that absorbs the yellow or sodium line in the viable light of the (spectrum) operation.




[Statutory Authority: RCW 49.17.010, 49.17.040, 49.17.050, 49.17.060. 05-03-093, § 296-304-04001, filed 1/18/05, effective 3/1/05; 03-04-099, § 296-304-04001, filed 2/4/03, effective 8/1/03. Statutory Authority: Chapter 49.17 RCW. 95-04-006, § 296-304-04001, filed 1/18/95, effective 3/10/95; 93-19-142 (Order 93-04), § 296-304-04001, filed 9/22/93, effective 11/1/93; Order 74-25, § 296-304-04001, filed 5/7/74.]