This subpart applies to OSVs of at least 6,000 GT ITC (500 GRT if GT ITC is not assigned), as defined in § 125.160 of this chapter.

(a) Electrical installations in hazardous locations, where necessary for operational purposes, must be located in the least hazardous location practicable.

(b) Electrical installations in hazardous locations must comply with the standards listed in paragraphs (b)(1), (2), or (3) of this section.

(1) NFPA 70 Articles 500 through 504 (incorporated by reference, see § 110.10-1 of this subpart). Equipment identified for Class I locations must meet the provisions of Sections 500.7 and 500.8 of NFPA 70 and must be tested and listed by an independent laboratory to any of the following standards:

(i) ANSI/UL 674, ANSI/UL 823, ANSI/UL 844, ANSI/UL 913, ANSI/UL 1203, ANSI/ISA 12.12.01, and/or ANSI/UL 2225 (incorporated by reference, see § 110.10-1).

(ii) FM Approvals Class Number 3600, Class Number 3610, Class Number 3611, Class Number 3615, Class Number 3620, or any combination of these (incorporated by reference, see § 110.10-1).

(iii) CSA C22.2 Nos. 0-10, 30-M1986, 157-92, and/or 213-16 (incorporated by reference, see § 110.10-1).

(2) NFPA 70 Article 505 (incorporated by reference, see § 110.10-1 of this subchapter). Equipment identified for Class I locations must meet the provisions of Sections 505.7 and 505.9 of NPFA 70 and be tested and listed by an independent laboratory to the ANSI/ISA Series of standards incorporated in NFPA 70.

(3) IEC 60092-502:1999 (incorporated by reference, see § 110.10-1), with the following exceptions:

(i) Section 111.106-5 of this subpart applies in lieu of Clause 7.3.1.

(ii) Section 111.106-9 of this subpart applies in lieu of Clause 4.2.

(iii) Section 111.106-7 of this subpart applies in lieu of Clauses 4.1.5 and 8.4.

(iv) Section 111.106-13(b) of this subpart applies in lieu of Clause 4.1.4 for enclosed areas containing devices handling hydrocarbons.

(v) Section 111.106-11 of this subpart applies in lieu of Clause 4.3.2.

(vi) Electrical apparatus in hazardous locations must meet one or the combination of IEC 60079-1:2014, IEC 60079-2:2014, IEC 60079-5:2015, IEC 60079-6:2015, IEC 60079-7:2015, IEC 60079-11:2011, IEC 60079-13:2017, IEC 60079-15:2017, IEC 60079-18:2017, IEC 60079-25:2010 or IEC 60079-30-1:2007 (all incorporated by reference, see § 110.10-1 of this subchapter) in lieu of Clause 6.5.

(vii) Equipment must be tested by an Ex Testing Laboratory and certified by an Ex Certification Body under the IECEx System, in lieu of Clause 6.3.

(c) As an alternative to paragraph (b)(1) of this section, electrical equipment that complies with the provisions of NFPA 496 (2017) (incorporated by reference, see § 110.10-1 of this subchapter) is acceptable for installation in Class I, Divisions 1 and 2. When equipment meeting this standard is used, it does not need to be identified and marked by an independent laboratory. The Commanding Officer, Marine Safety Center (MSC) will evaluate equipment complying with this standard during plan review. It is normally considered acceptable if a manufacturer's certification of compliance is indicated on a material list or plan.

(d) Equipment listed or certified to ANSI/UL 60079-18 or IEC 60079-18:2017, respectively (both incorporated by reference, see § 110.10-1), is not permitted in Class I Special Division 1 or Zone 0 hazardous location, unless the encapsulating compound of Ex “ma” protected equipment is not exposed to, or has been determined to be compatible with, the liquid or cargo in the storage tank.

(e) Lighting circuits serving flameproof or explosion-proof lighting fixtures in an enclosed hazardous space or room must—

(1) Have at least two lighting branch circuits;

(2) Be arranged so that there is light for relamping any de-energized lighting circuit;

(3) Not have the switch and overcurrent device within the space for those spaces containing explosion-proof or flameproof lighting fixtures; and

(4) Have a switch and overcurrent protective device that must open all ungrounded conductors of the circuit simultaneously.

(f) Submerged pump motors that do not meet the requirements of § 111.105-31(d), installed in tanks carrying flammable or combustible liquids with closed-cup flashpoints not exceeding 60 °C (140 °F), must receive concept approval by the Commandant (CG-ENG) and plan approval by the Commanding Officer, MSC.

(g) Wiring materials and cables in hazardous locations must meet the construction and testing requirements in § 111.106-5 of this subpart.

(h) Internal combustion engines installed in Divisions 1 and 2 (Zones 1 and 2) must meet the provisions of ASTM F2876-10 (incorporated by reference, see § 110.10-1).

(i) Cofferdams are required to separate enclosed spaces adjacent to integral cargo storage tanks.

(j) The cargo pumping/piping systems must be arranged independently from all other systems. Cargo transfer pumps and piping (including fill, discharge, vent, and sounding piping) must not be located in or pass through any accommodation, service, or machinery spaces.

(a) Cable and wiring in hazardous locations must meet the cable construction and testing provisions of IEEE 1580; ANSI/UL 1309; MIL-DTL-24640C; MIL-DTL-24643C; or 60092-350:2014 and IEC 60092-353:2016 (incorporated by reference, see § 110.10-1), including the respective flammability tests contained therein, and must be of a copper-stranded type.

(b) Type MC cables, when used, must meet the requirements in § 111.60-23 of this part.

(c) For intrinsically safe systems under the standards cited in § 111.106-3(b)(1) and (b)(2) of this subpart, the wiring methods must meet Section 504.30 of NFPA 70 (incorporated by reference, see § 110.10-1). For intrinsically safe systems under the standards cited in § 111.106-3(b)(3) of this subpart, the installation and wiring must meet Clause 7, except for Clause 7.3.1, of IEC 60092-502:1999 (incorporated by reference, see § 110.10-1).

(a) Hazardous location classification of adjacent spaces must comply with Clause 12.5 of either API RP 500 or API RP 505 (incorporated by reference, see § 110.10-1).

(b) A differential pressure-monitoring device or a flow-monitoring device, or both, must be provided for monitoring the pressurization of spaces having an opening into a more hazardous zone. A running fan motor or a fan-rotation monitoring device indicator is insufficient to satisfy this requirement.

(c) During initial startup, or after shutdown of the pressurization or ventilation system, and regardless of the classification of the hazardous location, the space must be ventilated or purged, followed by pressurization or ventilation of the space, before any electrical apparatus within the space may be energized. The atmosphere is considered non-hazardous when the concentration of explosive gases or vapors is below 30 percent of the lower explosive limit at all points in the space, equipment enclosures and vent ducts.

(d) Only electrical equipment and devices that are necessary for the operational purposes of the space may be installed in spaces made non-hazardous by the methods allowed in this section.

(a) This section applies to locations surrounding the storage and handling locations of flammable and combustible liquid cargoes with closed-cup flashpoints not exceeding 60 °C (140 °F).

(b) The following are Class I Special Division 1 (Zone 0) locations:

(1) Enclosed areas containing devices handling cargoes, such as cargo handling or pump rooms, except as modified by § 111.106-13 of this subpart.

(2) The interiors of cargo storage tanks, slop tanks, any pressure-relief pipework or other venting systems for cargo and slop tanks, pipes and equipment containing the cargo or developing flammable gases or vapors.

(3) Areas on an open deck, or a semi-enclosed space on an open deck, within 0.5 meters of any cargo storage tank outlet, cargo gas or vapor outlet, ullage opening, sounding pipe, cargo tank opening for pressure release, or cargo storage tank pressure or vacuum valve provided to permit the flow of small volumes of gas or vapor mixtures caused by thermal variation.

(4) Areas on an open deck, or semi-enclosed spaces on open deck, within 0.5 meters of any cargo handling or pump room entrance, or cargo ventilation handling or pump room ventilation inlet or outlet.

(5) Areas in the vicinity of any cargo vent outlet for free flow of large volumes of vapor mixtures during cargo loading and discharging of storage tanks, within a vertical cylinder of unlimited height, of 1 meter radius centered upon the vent outlet, and within a hemisphere of 1-meter radius below the vent outlet.

(6) Areas in the vicinity of any cargo high-velocity vent outlet during cargo loading and discharging of storage tanks, within a vertical cylinder of unlimited height, of 0.5 meters radius centered upon the vent outlet, and within a hemisphere of 0.5 meters radius below the vent outlet.

(c) The following are Class I Division 1 (Zone 1) locations:

(1) Areas on an open deck, or a semi-enclosed space on an open deck, that are 2.5 meters beyond the Class I Special Division 1 (Zone 0) areas cited in paragraphs (b)(3) and (4) of this section.

(2) Areas on an open deck, or a semi-enclosed space on an open deck, that are within 3 meters of any cargo manifold valve, cargo valve, cargo pipe flange, cargo tank hatch, sight port, tank cleaning opening, and opening into cofferdams or other Zone 1 spaces.

(3) Regardless of the level of natural ventilation, areas on an open deck above the tank top of each cargo tank extending out 3 meters beyond the tank top boundaries of each cargo tank, up to a height of 2.4 meters above the deck.

(4) Areas on an open deck within spillage coamings surrounding cargo manifold valves extending 3 meters beyond the boundaries of the spillage coamings, up to a height of 2.4 meters.

(5) A void space or an enclosed space immediately above, below or adjacent to an integral cargo storage tank, including cofferdams and permanent (for example, segregated) ballast tanks adjacent to integral cargo storage tanks.

(6) A hold space containing an independent cargo storage tank.

(7) Compartments for cargo transfer hoses.

(8) Enclosed or semi-enclosed spaces in which pipes containing cargoes are located.

(9) Areas 7.5 meters beyond the cylinder and 7.5 meters beyond the hemisphere of the Class I Special Division 1 (Zone 0) hazardous locations cited in paragraph (b)(5) of this section.

(10) Areas 5.5 meters beyond the cylinder and 5.5 meters beyond the hemisphere of the Class I Special Division 1 (Zone 0) hazardous locations cited in paragraph (b)(6) of this section.

(d) The following are Class I Division 2 (Zone 2) locations:

(1) Areas on an open deck, or a semi-enclosed space on an open deck, that are 1.5 meters beyond the Class I Division 1 (Zone 1) areas cited in paragraphs (c)(1) through (4) of this section.

(2) Areas 1.5 meters beyond the cylinder and 1.5 meters beyond the hemisphere of the Class I Special Division 1 (Zone 1) hazardous locations cited in paragraph (c)(9) of this section.

(3) Areas 4 meters beyond the cylinder and 4 meters beyond the hemisphere of the Class I Division 1 (Zone 1) hazardous locations cited in paragraph (c)(10) of this section.

(4) Enclosed spaces beyond the open deck areas cited in paragraph (c)(3) of this section that are below the level of the main deck and have an opening onto the main deck or at a level less than 0.5 meters above the main deck, unless—

(i) The entrances to such spaces, including ventilation inlets and outlets, are situated at least 5 meters from the closest integral cargo tank bulkhead and at least 10 meters measured horizontally from any integral cargo tank outlet or gas or vapor outlet; and

(ii) The spaces are mechanically ventilated.

(a) This section applies to locations surrounding the storage and handling of combustible liquid cargoes with closed-cup flashpoints exceeding 60 °C (140 °F).

(b) The interiors of independent storage tanks and integral tanks containing cargoes with closed-cup flashpoints of 60 °C (140 °F) or higher and heated to within 15 °C of their flashpoint are considered Class I Special Division 1 (Zone 0). The hazardous locations in § 111.106-9 of this subpart apply.

(a) This section is applicable to enclosed areas containing devices handling flammable or combustible liquid cargoes with closed-cup flashpoints not exceeding 60 °C (140 °F).

(b) Enclosed hazardous locations containing devices that handle cargoes must comply with Clauses 6.3.1.2 of API RP 500 and 6.6.1.2 of API RP 505 (incorporated by reference, see § 110.10-1). Ventilation must not be used to reduce the classification of such areas.

(c) Cargo pump rooms must be isolated from all sources of vapor ignition by gastight bulkheads. The gastight bulkhead between the pump room and the pump-motor compartment may be pierced by fixed lights, drive shafts, and pump-engine control rods, provided that the shafts and rods are fitted with fixed oil reservoir gland seals, or pressure grease seals where they pass through the gastight bulkheads. Other types of positive pressure seals must be specially approved by the Commandant (CG-ENG). Access to a cargo handling enclosed area or room must be from the open deck.

(d) Fixed lights in cargo pump rooms or enclosed cargo handling areas must meet the arrangement and construction requirements in § 111.105-31(g) of this part.

(e) A cargo handling area or pump room that precludes the lighting arrangement of paragraph (d) of this section, or where the lighting arrangement of paragraph (d) of this section does not give the required illumination level, must have explosion-proof, flameproof (Ex “d”) or flameproof-increased safety (Ex “de”) lighting fixtures.

(a) The ventilation design principles must comply with Clauses 8.1.3, 8.2, and 8.3 of IEC 60092-502:1999 (incorporated by reference, see § 110.10-1).

Note to § 111.106-15(a): The word “mechanical,” as used in this section, is interchangeable with the word “artificial” used in IEC 60092-502:1999.

(b) A ventilation system must—

(1) Be positioned so as not to recycle vapors from ventilation discharges;

(2) Have its operational controls outside the ventilated space, if the system is mechanical; and

(3) Have a protective metal screen of not more than 13 mm (0.512 in.) square mesh on each ventilation intake and exhaust opening.

(c) The mechanical ventilation of enclosed flammable or combustible liquid cargo handling or cargo pump rooms must be sufficient to effect a minimum complete 30 air changes per hour based on the volume of the pump room and associated trunks up to the deck at which access from the weather is provided. The power ventilation system must be designed to remove vapors from the bottom of the space at points where concentrations of vapors may be expected.

(d) The following spaces must have a supply-type mechanical ventilation system capable of providing at least 8 air changes per hour:

(1) Each space that contains electric motors for cargo handling equipment.

(2) Each cargo control station.

(a) Tanks or piping systems that are separated from the hull structure by thermal isolation must be electrically bonded to the hull structure by a method under paragraph (c) of this section.

(b) A pipe joint or a hose connection fitting that has a gasket must be electrically bonded by a method under paragraph (c) of this section that bonds—

(1) Both sides of the connection to the hull structure; or

(2) Each side of the connection to the other side.

(c) An electrical bond must be made by at least one of the following methods:

(1) A metal bonding strap attached by welding or bolting;

(2) Two or more bolts that give metal-to-metal contact between the bolts and the parts to be bonded; or

(3) Other metal-to-metal contact between adjacent parts under designed operating conditions.