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6. Part 6 - Machinery and Electrical Installations in Hazardous Locations for all Types of Units

Part 6 - Machinery and Electrical Installations in Hazardous Locations for all Types of Units

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Electrical Installations in Hazardous Locations

55. (1) Every electrical installation in a hazardous location shall comply with Section 18, of the Canadian Electrical Code, Part I except as modified by this section.

(2) Equipment shall be approved not only for the class of location but also for the explosive, combustible, or ignitible properties of the specific gas or vapour that will be present and equipment shall not have exposed any surface that operates at a temperature in excess of the ignition temperature of the specific gas or vapour.

(3) Equipment that has been approved for a Division 1 location shall be permitted in a Division 2 location of the same class and group and equipment which requires to be approved shall be listed by the Canadian Standards Association, Underwriters Laboratories, Factory Mutual Research Corporation or other independent laboratory recognized by the Board for use in the hazardous location in which it is located.

(4) Each item of electrical equipment that is required under this section to be explosion-proof shall be listed by the Canadian Standards Association, Underwriters Laboratories, Factory Mutual Research Corporation or other independent laboratory recognized by the Board; special consideration may be given by the Board to consider "increased safety " equipment for installation in Class I, Division 2 locations provided that a certificate from an independent laboratory is submitted for evaluation; the Board may also consider electrical equipment certified Ex(d)(e) for Class I, Division I locations provided that a certificate from an independent test laboratory is submitted for evaluation.

(5) Subject to subsection (6) distribution systems with grounded neutrals, grounded phases or with hull return shall not be used in hazardous locations.

(6) Special approval for the use in hazardous locations of systems prescribed in subsection (5) may be granted for

1. impressed current cathodic protective systems;
2. insulation level monitoring devices provided the circulation current does not exceed 30 milliamperes above an established base level under the most unfavourable conditions; and
3. limited and locally grounded systems.

(7) Where a subsection states that an electric system is to be intrinsically safe for use in a hazardous location, the system shall be listed as intrinsically safe by Canadian Standards Association, Underwriters Laboratories, Factory Mutual Research Research Corporation or other independent laboratory recognized by the Board and shall comply with the following:

1. each electric cable for an intrinsically safe system shall
   1. be 50 millimetres or more from cable of non-intrinsically safe circuits; or
   2. be partitioned by a grounded metal barrier from other non-intrinsically safe electric cables; or
   3. be a shielded cable;
2. the manufacturer shall submit installation instructions and restrictions on the approved system; typical restrictions that must be specified include
   1. voltage limitations;
   2. allowable cable parameters;
   3. maximum length of cable permitted; and
   4. ability of system to accept passive devices;
3. intrinsically safe systems shall not be interconnected unless the systems were approved with the particular arrangement; and
4. the deck wiring diagram required by paragraph 7(1)(c) shall specify
   1. system identification as to manufacturer's model number;
   2. system use;
   3. cable parameter including length and type of cable;
   4. wiring and equipment locations; and
   5. installation details.

(8) Purged and pressurized equipment shall meet the requirements of the National Fire Protection Association No. 496 or as approved by the Board.

(9) Wiring methods for Class I hazardous locations shall be in accordance with the following:

1. cable for Class I, Division 1, hazardous locations, except as provided in paragraphs (b) and (c) of this subsection shall
   1. be approved braided marine or MI type cable; or
   2. be approved cable installed in threaded rigid metal conduit;
2. cable for use in an intrinsically safe system shall meet
   1. the requirements of section 12, Ship Safety Electrical Standards, TP-127; and
   2. the recommendations of ISA RP 12.6 issued by The Instrument Society of America for 'Installation of Intrinsically Safe Instrument Systems in Class 1 Hazardous Locations', except Appendix A.1;
3. flexible cords and cables shall be C.S.A. certified for extra hard usage or as approved by the Board;
4. each explosion-proof enclosure that is in a Class I location shall have an approved explosion-proof seal fitting that is
   1. threaded directly into the enclosure; or
   2. connected to the enclosure by a piece of approved explosion-proof rigid metal conduit that is 460 millimetres or less in length;
5. cable for Class I, Division 2 hazardous locations, except as provided in paragraphs (a), (b) and (c) of this subsection shall
   1. meet the requirements of section 12, Ship Safety Electrical Standards TP-127; and
   2. be protected from mechanical damage.

(10) Each explosion-proof switch and each switch controlling explosion-proof equipment shall have a pole for each circuit conductor.

(11) Each fan for ventilation of a hazardous location shall be so designed as to render sparking impossible in the event of the impeller tips touching the fan casing.

(12) Each electric motor for a fan that ventilates a hazardous location shall be listed by the Canadian Standards Association, Underwriters Laboratories, Factory Mutual Research Corporation or other independent laboratory recognized by the Board for the same class, division, and group as the ventilated location; or be

1. outside the ventilation duct;
2. 3 metres from the ventilation duct termination; and
3. in a non-hazardous location.

(13) Equipment mounted in a ventilation duct which ventilates a hazardous location shall meet the classification requirements of that space.

(14) Each belt drive in a hazardous location shall have

1. a conductive belt i.e. anti-static; and
2. pulleys, shafts, and driving equipment grounded to meet the National Fire Protection Association, No. 77.

(15) The internal space of each pressure vessel, closed tank, and pipe for drilling mud and for gas venting shall have only certified intrinsically safe circuits or equipment and associated wiring.

(16) Distribution systems, except, intrinsically safe circuits, feeding or passing through a hazardous location referred to in this section shall have a device capable of continously monitoring the insulation level to ground and giving an audible alarm at a manned position when ground fault current exceeds 30 milliamperes above an established base level.

(17) Electrical equipment and wiring installed in hazardous locations shall be limited to that necessary for operational purposes and only the cables and types of equipment described in this Part may be installed.

Classification of Hazardous Locations

56. (1) The following are Class I, Division 1 locations:

1. an enclosed space that contains any part of the active mud circulating system that has an opening into the space and is between the well and the final degassing discharge;
2. an enclosed or semi-enclosed area that is below the drill floor and contains a possible source of gas release, such as the top of a drilling nipple;
3. an enclosed space that is on the drill floor and is not separated by a solid gastight floor from the spaces specified in paragraph (1)(b);
4. an outdoor or a semi-enclosed area except as provided in paragraph (1)(b), that is within 1.5 metres of the boundary of any
   1. equipment or opening specified in paragraph (1)(a); and
   2. ventilation outlet or access opening to a Class I, Division 1 space;
5. pits, ducts or similar structures in locations which otherwise would be Class 1, Division 2 but which are arranged so that dispersion of gas may not occur.

(2) The following are Class I, Division 2 locations:

1. an enclosed space which contains open sections of the active mud circulating system from the final degassing discharge to the mud pump suction connection at the mud pits;
2. an outdoor area within the boundaries of the drilling derrick up to a height of 3 metres above the drill floor;
3. a semi-enclosed area below and contiguous to the drill floor and to the boundaries of the derrick or to the extent of any enclosure which is liable to trap gas;
4. an outdoor area below the drill f loor and within a radius of 3 metres from a possible source of release such as the top of a drilling nipple;
5. an area 1.5 metres beyond the Class I, Division 1 locations specified in paragraph (1)(d) and beyond the semi-enclosed locations specified in paragraph (1)(b);
6. an outdoor area within 1.5 metres of the boundaries of any ventilation outlet from or access to a Class I, Division 2 location; and
7. a semi-enclosed derrick to the extent of the enclosure above the drill floor or to a height of 3 metres above the drill floor, whichever is greater.

Openings, Access and Ventilation Conditions Affecting the Extent of Hazardous Locations

57. (1) Except as provided in subsection (2) access doors or other openings shall not be provided between

1. a non-hazardous space and a hazardous area; and
2. a Class I, Division 2 and a Class I, Division 1.

(2) Where such access doors or other openings are provided any enclosed space not referred to under subsections 56(1) or (2) and having a direct access to any Class I, Division 1 location or Class I, Division 2 location becomes the same division as the location except that

1. an enclosed space with direct access to any Class I, Division 1 location can be considered as Class I, Division 2 if
   1. the access is fitted with a gas-tight door opening into the Class I, Division 2 space;
   2. ventilation is such that the air flow with the door open is from the Class I, Division 2 space into the Class I, Division 1 location; and
   3. loss of ventilation is alarmed at a manned station;
2. an enclosed space with direct access to any Class I, Division 2 location is not considered hazardous if
   1. the access is fitted with a self-closing gas-tight door that opens into the non-hazardous location;
   2. ventilation is such that the air flow with the door open is from the nonhazardous space into the Class I, Division 2 location; and
   3. loss of ventilation is alarmed at a manned station;
3. an enclosed space with direct access to any Class I, Division 1 location is not considered hazardous if
   1. subject to subparagraph (iv) the access is fitted with gas-tight selfclosing doors forming an air-lock;
   2. the space has ventilation overpressure in relation to the hazardous space;
   3. loss of ventilation overpressure is alarmed at a manned station; and
   4. where ventilation arrangements of the intended safe space are considered sufficient by the Board to prevent any ingress of gas from the Class I, Division 1 location, the two self-closing doors forming an air-lock may be replaced by a single gas-tight self-closing door which opens into the nonhazardous location and has no hold-back device.

(3) Piping systems shall be designed to preclude direct communications between hazardous locations of different divisions and between hazardous and nonhazardous areas.

Ventilation of Spaces

58. (1) Hazardous enclosed spaces shall be ventilated and where mechanical ventilation is applied it shall be such that the hazardous enclosed spaces are maintained with underpressure in relation to the less hazardous spaces or areas and non-hazardous enclosed spaces are maintained in overpressure in relation to adjacent hazardous locations.

(2) All air inlets for hazardous enclosed spaces shall be taken from nonhazardous areas and where the inlet duct passes through a more hazardous area the inlet duct is to have overpressure in relation to this area.

(3) Each air outlet shall be located in an outdoor area which in the absence of the considered outlet is of the same or lesser hazard than the ventilated space.

Emergency Shutdown Procedures

59. (1) In view of exceptional conditions in which the explosion hazard may extend outside the above mentioned locations special arrangements shall be provided for the disconnection or shutdown either selectively or simultaneously of all electrical equipment and or devices except those services required by subsections 51(6) and (7); the emergency shut down facilities shall be provided at the drilling console and in a continually manned control room and the recommended sequence of shut-down shall be provided in the Operating Manual.

(2) Electrical shut-down systems that are provided to comply with this section shall be designed so that the risk of unintentional stoppages caused by malfunction in a shut-down system or of inadvertent operation of a shut-down are minimized.

Machinery Installations in Hazardous Locations

60. (1) Mechanical equipment shall be limited to that necessary for operational purposes.

(2) mechanical equipment and machinery in hazardous locations shall be so constructed and installed as to reduce the risk of ignition from sparking due to the formation of static electricity or friction between moving parts and from high temperature of exposed parts.

(3) Boilers and other fired appliances in which a naked flame may be present shall be located in compartments which are non-hazardous.

(4) The installation of internal combustion engines may be permitted in hazardous locations subject to the following minimum requirements:

1. Class I, Division 1:
   1. the engine shall be installed in a pressurized compartment;
   2. the pressurization air shall be taken from a safe area;
   3. a pressure of 5 millimetres water gauge shall be maintained with one door fully open;
   4. the compartment shall be fitted with an alarm activated upon pressure failure; and
   5. the compartment shall be fitted with an access air lock system of double self-closing doors;
2. Class I, Division 2:
   1. the engine air intake and exhaust shall be led from and to safe areas;
   2. the air intake shall be fitted with an efficient flame arrester;
   3. the exhaust manifold surface temperature shall not exceed 200°C;
   4. the exhaust system shall be fitted with an efficient flame trap/spark arrester; and
   5. starting arrangements shall be by pneumatic or hydraulic means.

Portable Structures in Hazardous Locations

61. (1) Portable structures installed in hazardous locations shall be fitted with

1. a smoke detection system wired back to the main fire detection panel;
2. a pressurized ventilation system that maintains ventilation overpressure in relation to the hazardous space;
3. loss of ventilation overpressure alarmed at a manned station; and
4. a ventilation shut down arrangement.

(2) The fire alarm, general alarm and public address systems shall be clearly audible inside the portable structure.

(3) Details and arrangement of the portable structure including the deck mounting arrangement shall be submitted to the Board for approval.

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Date modified:

2010-01-25

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