Section 1915.4 - Definitions(a) The term SHALL indicates provisions which are mandatory.(b) The term Secretary means the Secretary of Labor.(c) The term employer means an employer, any of whose employees are employed, in whole or in part, in ship repairing, shipbuilding, shipbreaking or related employments as defined in this section on the navigable waters of the United States, including dry docks, graving docks and marine railways.(d) The term employee means any person engaged in ship repairing, shipbuilding, shipbreaking or related employments on the navigable waters of the United States, including dry docks, graving docks and marine railways, other than the master, ship's officers, crew of the vessel, or any person engaged by the master to repair any vessel under 18 net tons.(e) The term gangway means any ramp-like or stair-like means of access provided to enable personnel to board or leave a vessel including accommodation ladders, gangplanks and brows.(f) The term vessel includes every description of watercraft or other artificial contrivance used, or capable of being used, as a means of transportation on water, including special purpose floating structures not primarily designed for or used as a means of transportation on water.(g) For purposes of § 1915.74 , the term barge means an unpowered, flat bottom, shallow draft vessel including scows, carfloats and lighters. For purposes of this section, the term does not include ship shaped or deep draft barges.(h) For purposes of § 1915.74 , the term river tow boat means a shallow draft, low free board, self-propelled vessel designed to tow river barges by pushing ahead. For purposes of this section, the term does not include other towing vessels.(i) The term shipyard employment means ship repairing, shipbuilding, shipbreaking and related employments.(j) The terms ship repair and ship repairing mean any repair of a vessel including, but not restricted to, alterations, conversions, installations, cleaning, painting, and maintenance work.(k) The term shipbuilding means the construction of a vessel including the installation of machinery and equipment.(l) The term shipbreaking means any breaking down of a vessel's structure for the purpose of scrapping the vessel, including the removal of gear, equipment or any component part of a vessel.(m) The term related employment means any employment performed as an incident to or in conjunction with ship repairing, shipbuilding or shipbreaking work, including, but not restricted to, inspection, testing, and employment as a watchman.(n) The term hazardous substance means a substance which by reason of being explosive, flammable, poisonous, corrosive, oxidizing, irritant, or otherwise harmful is likely to cause injury.(o) The term competent person for purposes of this part means a person who is capable of recognizing and evaluating employee exposure to hazardous substances or to other unsafe conditions and is capable of specifying the necessary protection and precautions to be taken to ensure the safety of employees as required by the particular regulation under the condition to which it applies. For the purposes of subparts B, C, and D of this part, except for § 1915.35(b)(8) and § 1915.36(a)(5) , to which the above definition applies, the competent person must also meet the additional requirements of § 1915.7 .(p) The term confined space means a compartment of small size and limited access such as a double bottom tank, cofferdam, or other space which by its small size and confined nature can readily create or aggravate a hazardous exposure.(q) The term enclosed space means any space, other than a confined space, which is enclosed by bulkheads and overhead. It includes cargo holds, tanks, quarters, and machinery and boiler spaces.(r) The term hot work means riveting, welding, burning or other fire or spark producing operations.(s) The term cold work means any work which does not involve riveting, welding, burning or other fire or spark producing operations.(t) The term portable unfired pressure vessel means any pressure container or vessel used aboard ship, other than the ship's equipment, containing liquids or gases under pressure, excepting pressure vessels built to Department of Transportation regulations under 49 CFR part 178, subparts C and H.(u) The term powder actuated fastening tool means a tool or machine which drives a stud, pin, or fastener by means of an explosive charge.(v) For purposes of § 1915.97 , the term hazardous material means a material which has one or more of the following characteristics:(1) Has a flash point below 140 °F., closed cup, or is subject to spontaneous heating;(2) Has a threshold limit value below 500 p.p.m. in the case of a gas or vapor, below 500 mg./m.3 for fumes, and below 25 m.p.p.c.f. in case of a dust;(3) Has a single dose oral LD50 below 500 mg./kg.;(4) Is subject to polymerization with the release of large amounts of energy;(5) Is a strong oxidizing or reducing agent;(6) Causes first degree burns to skin in short time exposure, or is systemically toxic by skin contact; or(7) In the course of normal operations, may produce dusts, gases, fumes, vapors, mists, or smokes which have one or more of the above characteristics.47 FR 16986, Apr. 20, 1982, as amended at 67 FR 44541 , July 3, 2002