HOT WORK ON HOLLOW OR ENCLOSED STRUCTURES

IN SHIPYARD EMPLOYMENT

 

Hot work on a hollow or enclosed structure located on a vessel or
shoreside can present a hazard to both the worker and vessel/facility.
Hot work includes welding, burning, brazing or cutting with abrasive or
metal blades into a hollow or enclosed structure (29 CFR § 1915.54(a)
and (c); 1915.11(b); 1915.51(b) and (d)).

Hollow or enclosed structures are drums, inaccessible voids, sealed
bulkheads, hatches and coamings, skegs, bilge keels, rudders,
fairwaters, pipe stanchions, masts, booms, lamp posts, crane pedestals,
lapped-plates, doubler-plates, railings, rub-rails, mooring bitts and
bollards, vents, container frames, box girders, cargo lids, sponsons,
pontoons, floats, buoy and many others (29 CFR 1915.54; 1915.12). 

Hollow or enclosed structures should not be confused with tanks or
confined and enclosed spaces. Work on these spaces have different
regulations found under (29CFR 1915.12). 

Known hazards of hollow and enclosed structures are: 

May contain flammable or toxic gases, liquids, or residues 

Commonly filled with combustible preservatives 

Often contaminated with saltwater, fuel oils, solvents, and degreasers
or cleaning chemicals 

May contain high pressure or vacuum effects due to fluctuation in
temperatures. 

Recommended control measures to be taken prior to hot work: 

Always wear proper PPE, clothing, gloves and eye protection during
drilling, cutting and hot work operations. (29 CFR 1915.152(a),
1915.153(a),(b)) 

Inspect any adjacent areas which may be affected by the hot work to
ensure any combustible material is removed, covered or isolated.

Open all sampling ports to drain residual products and get a Shipyard
Competent Person to test for the presence of flammable gases or liquids
using a combustible gas detector, if available (29 CFR 1915.54(c)).

 

When a sampling port is not available, drill a small hole into the
structure to facilitate air sampling and testing. Use sharp bits and
blades, always lubricate the drilling bits and metal blades with cutting
oil or soapy water to minimize the generation of heat and sparks (29 CFR
1915.54(a), 1915.51(c)). 

If any flammable gases, liquids or preservatives are detected and gas
reading is above 10% LEL, consult a Shipyard Competent Person or an NFPA
Certified Marine Chemist (29 CFR 1915.14(a) and (b); 1915.540).
Carefully drill a second hole further away to ventilate by blowing
compressed air through the structure.  After the structure is
ventilated, retest again to ascertain 0% LEL is sustained prior to any
hot work (29 CFR 1915.12(b); 1915.14(a) and (b)(1)). 

MACOSH QUICK CARD			 Exhibit 16

