OHS Code

Published Date: July 01, 2009
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Part 10 Fire and Explosion Hazards

Section 168 Industrial furnaces and fired heaters

(1) An employer must ensure that

(a) a gas or oil fired furnace is designed, operated, monitored, controlled and maintained in a manner that minimizes the possibility of internal explosion of the fire box, and

(b) if the furnace is heating flammable substances, there are no connections between the process medium supply system and the fuel supply system or another system connected to the inside of the fire box of the furnace.

(2) An employer must ensure that the heated substance systems referred to in subsection (1)(b) are not isolated using inserted blinds or a double block and bleed system.

(3) A worker must not attempt to ignite a furnace manually, or to re-ignite a furnace after shutdown, until

(a) explosive concentrations of flammable substances are eliminated from the fire box by purging or removed by another effective means, and

(b) tests or procedures are completed that ensure an explosive atmosphere is not present within the furnace.

(4) An employer must ensure that intakes, exhausts and the fire box of a furnace or fired heater are not located or operated in a Division 1, Zone 0 or Zone 1 hazardous location of any Class under the Canadian Electrical Code.

(5) An employer must ensure that a furnace or fired heater is not located or operated in a Division 2 or Zone 2 hazardous location of any Class as defined in the Canadian Electrical Code, unless

(a) the combustion process is totally enclosed except for the combustion air intake and the exhaust discharge,

(b) all surfaces exposed to the atmosphere

(i) operate below the temperature that would ignite a flammable substance present in the hazardous location, or

(ii) are shielded or blanketed in such a way as to prevent a flammable substance in the hazardous location from contacting the surface, and

(c) the combustion air intake and exhaust discharge are equipped with a flame arresting device or are located outside the hazardous location.

(6) If it is not reasonably practicable to comply with subsection 5(b), an employer must ensure that another effective safeguard is established.