511 EM 385-1-1 Chapters 9-15

Sections

10-8. General Requirements.

Welding and Cutting Hazardous Materials (HAZMAT)

Perform welding, cutting, and heating on pipelines according to regulations, specifically 49 CFR 192.
Test and remove flammable preservative coatings before welding, cutting, or heating, and strip toxic surface coatings in enclosed spaces as per safety assessments.
When dealing with toxic materials, use appropriate ventilation and personal protective equipment (PPE), and follow specific guidelines for materials like beryllium or chromium (VI).

Critical Items

Structural welding on critical items must be done by certified welders.
Welds on critical items need inspection by a qualified welding inspector.

Oxyfuel Gas Welding and Cutting

Use NRTL approved oxyfuel gas welding and cutting equipment.
Store and handle oxygen cylinders and apparatus carefully, keeping them free from flammable substances and ensuring they are not used interchangeably with other gases.
Ensure hose safety by making them distinguishable, non-interchangeable, and regularly testing them, especially after exposure to damage or wear.

Knowledge Check Choose the best answer for the question.

10-7. What should be done before welding, cutting, or heating on surfaces with flammable preservative coatings?

Test and remove the coatings

Sand them with abrasives

Nothing, if fumes are not produced

Limit welding duration

You forgot to answer the question!

EM 385-1-1 Paragraph 10-8 (e.–g.).

10-8. General Requirements. (e.–g.).

e.  Welding and Cutting Hazardous Materials (HAZMAT).  (10-8.e)

(1)  Perform welding, cutting, and heating operations on pipelines according to 49 CFR 192.

(2)  Test all surfaces covered by a preservative coating whose flammability is not known to determine its flammability before starting to weld, cut, or heat them. Preservative coatings are considered highly flammable when scrapings burn with extreme rapidity.

(a)  Remove preservative coatings a sufficient distance from the area to be heated to ensure any temperature increase of the un-stripped metal will not result in visually observable decomposition or degradation of the coatings.  Artificial cooling of the metal surrounding the heated area may be used to limit the area to be stripped.

(b)  When welding, cutting, or heating toxic surface coatings (for example, paints, preservatives, surface stripping chemicals) in enclosed spaces, strip all surfaces covered with the coatings a distance of at least 4 inches (10.2 cm) from the area of heat application or use airline respirators as deemed necessary by a CP assessment and according to chapter 6.

(3)  Materials of toxic significance.  Perform welding, cutting, or heating operations that involve or generate any of the toxic substances listed below according to the following requirements:  antimony, arsenic, barium, beryllium, cadmium, chromium, chromium (VI), cobalt, copper, lead, manganese, mercury, nickel, ozone, selenium, silver, or vanadium.

(a)  Whenever these materials are encountered in confined space, use intrinsically safe local exhaust ventilation and PPE.

(b)  Whenever these materials, except beryllium or chromium (VI), are encountered in indoor operations, use, and maintain local mechanical exhaust ventilation systems that are sufficient to reduce and maintain personal exposures to within acceptable limits according to the manufacturer’s instructions. Ensure that replacement filters are from the same manufacturer and are the correct filter for the exhaust system. When either beryllium or chromium (VI) is encountered in indoor operations, use approved local mechanical exhaust ventilation systems and personal respiratory protection. (See chapter 6)

(b-1)  In areas where only welding is conducted, use a general exhaust system ventilation rate of at least 2,000 cubic feet per minute (CFM) (0.9 m3/s) per welder in open welding areas.

(b-2)  Local exhaust ventilation must have a capture velocity of 100 fpm (0.5 m/s), as measured from the farthest distance from the work, and a duct transport velocity of at least 1,000 fpm (5.1 m/s).  Local exhaust ventilation systems that filter and return the air back into the work environment are allowed for welding if the work is not located in a confined space or does not involve beryllium or chromium and if the provisions of chapter 6 are followed.

(c)  Whenever these materials, except beryllium or chromium (VI), are encountered in outdoor operations, and local mechanical exhaust ventilation systems sufficient to reduce and maintain personal exposures to within acceptable limits are not provided, appropriate respiratory protective equipment must be used (see chapter 6).

(d)  Whenever beryllium or chromium (VI) are encountered in outdoor operations, base the justification for and the implementation of engineering and work practice controls and respiratory protection on the results of an initial worker exposure assessment and an exposure determination (see para 10-8.i and chapter 6).

(e)  Workers may be exposed to hazardous concentrations of chromium (VI) while welding, cutting, or performing hot work on stainless steel, high chrome alloys or chrome coated metal, or during the application and removal of chromate-containing paints, and other surface coatings (see chapter 6).

(f)  When working with materials of toxic significance, workers must remove outer clothing, vacuum off, and wash before taking a break, drinking, smoking, or leaving for the day.

(4)  Perform welding, cutting, or heating operations that involve or generate fluorine or zinc compounds according to the following:

(a)  In confined spaces, use local mechanical exhaust ventilation and personal respiratory protection sufficient to maintain exposures within acceptable limits (see chapter 6).

(b)  In open spaces, perform sampling and testing according to the procedures in chapter 6 to determine concentrations of fluorides or zinc compounds and the need for local exhaust ventilation and personal respiratory protection sufficient to maintain exposures within acceptable limits.

f.  Critical Items. (10-8.f)

(1)  All structural welding performed on critical items (for example, scaffolding, shoring, forms, ladders, piling), as well as other critical items as determined by QP, must only be performed by certified welders (see para 10-3.c).

(2)  Welds on critical items must be inspected by either a current CSWI, a CWI, or equivalent welding inspector trained to AWS standards (see paras 10-3.c and 10-4.a).

g.  Oxyfuel Gas Welding and Cutting.  (10-8.g)

(1)  Oxyfuel gas welding and cutting equipment must be approved by NRTL.

(2)  Oxygen Cylinders and Apparatuses.

(a)  Keep oxygen cylinders and apparatus free from oil, grease, and other flammable or explosive substances.  Do not handle them with oily hands or gloves.

(b)  Do not use oxygen cylinders and apparatus interchangeably with any other gas.

(3)  Hose and Hose Connections.

(a)  Fuel gas hose and oxygen hose must be readily distinguishable from each other.

(b)  Oxygen and fuel gas hoses are not interchangeable.  Do not use a single hose having more than one gas passage.

(d)  Test hoses that have been subjected to flashback or that shows evidence of severe wear or damage to twice the normal pressure to which it is subjected.  In no case test with less than 300 psi (2068.4 kPa) gauge.  Do not use damaged hose and hose connectors, or hose and hose connectors in questionable condition.

(e)  When parallel runs of oxygen and fuel gas hose are taped together, not more than 4 inches out of every 12 inches (10.2 cm out of every 30.4 cm) may be covered by tape.

(f)  Properly ventilate all boxes used for the storage of gas hoses and all enclosed spaces containing gas hoses.

(g)  Clamp or otherwise securely fasten hose connections in a manner that will withstand, without leakage, twice the pressure to which they are normally subjected in service, but not less than 300 psi (2,068 kPa) gauge.

(4)  Torches.

(a)  Inspect torches before each use for leaking shutoff valves, hose couplings, tip connections, and damaged torch tips.  Do not use defective torches.

(b)  Hoses must be purged individually before lighting the torch for the first time each day. Do not purge hoses into confined spaces or near ignition sources.

(d)  Light torches with friction lighters or other approved devices; not by matches or from hot work.

(e)  Close torch valves and shut off the gas supply whenever work is suspended.

(f)  Remove the torch and hose from confined spaces whenever work is suspended.

(5)  Protective Equipment.

(a)  Unless indicated otherwise by the manufacturer’s instructions, install a reverse-flow check valve and a flash arrestor in the hose at each torch when using oxyfuel gas or other oxygen-fuel gas welding and cutting systems that use a cylinder regulator-hose-torch.

(b)  When oxygen-fuel gas systems are manifolded together, perform according to NFPA 51.

(6)  Do not connect multiple sets of oxyacetylene hoses to a single regulator on a single set of oxyacetylene tanks unless a commercially available fitting that complies with CGA standards and is listed by a NRTL is installed.  Install the fitting in the output side of the regulator and include a built-in shut-off valve and reverse-flow check valve on each branch.

(7)  Do not adjust acetylene regulators to permit a discharge greater than 15 psi
    (103.4 kPa) gauge.