Canada–Nova Scotia Offshore Area Petroleum Operations Framework Regulations — 114
Ventilation of enclosed hazardous areas 114 (1) An operator must ensure that any enclosed hazardous area on an installation is ventilated such that (a) air is replaced at a rate sufficient to prevent hazardous gas accumulations in the enclosed hazardous area; (b) all air entering the enclosed hazardous area is from a non-hazardous area; (c) the air exhausted from the enclosed hazardous area does not increase the hazard level in another enclosed hazardous area or create a hazard in an enclosed non-hazardous area; and (d) the ventilation system for the enclosed hazardous area is separate from the ventilation system for any non-hazardous area. Mechanical ventilation system (2) If a mechanical ventilation system is used for the purposes of subsection (1), the operator must ensure that the air in the enclosed hazardous area is maintained at a pressure that is lower than the pressure of any adjacent non-hazardous area or any adjacent hazardous area that is classified as less hazardous. Air exhaustion from enclosed hazardous area (3) The operator must ensure that all air exhausted from an enclosed hazardous area is vented to an outdoor area that, were it not for the vented air, would be a non-hazardous area or a hazardous area that would be classified as no more hazardous than the enclosed hazardous area. Ventilation pressure differential and functionality (4) The operator must ensure that measuring devices are installed that will monitor any loss of ventilation pressure differential and any loss of functionality of each ventilation system for a hazardous area and that will, no more than 30 seconds after such a loss occurs, activate audible and visual alarms at the control points from which the system is monitored. Positive overpressure relative to atmospheric pressure (5) The operator must, in respect of the main control centre and all accommodations areas on an installation, ensure that (a) they are maintained at a positive overpressure relative to atmospheric pressure; (b) all of their external doors that provide a primary means of access to them are equipped with airlocks; and (c) all of their other external doors are equipped with airlocks or other means of maintaining and monitoring positive overpressure relative to atmospheric pressure. Power shut-off for mechanical ventilation system (6) The operator must ensure that the power source for a mechanical ventilation system that serves a hazardous area, a work area in a non-hazardous area or an accommodations area is capable of being shut off from the control station and from a position that is outside the area being ventilated and that will remain accessible during any fire that may occur within that area. Inlets and outlets of ventilation systems (7) The operator must ensure that the main inlets and outlets of all ventilation systems are capable of being closed from a position that is outside the area being ventilated and that will remain accessible during any fire that may occur within that area. Ventilation system in non-hazardous area (8) The operator must ensure that any ventilation system that serves a non-hazardous area is equipped with emergency devices in the event of a mechanical ventilation failure or the detection of hazardous gas, including (a) measuring devices to monitor any loss of ventilation pressure differential; (b) audible and visual alarms; (c) an automated isolation device to prevent hazardous gas from entering the non-hazardous area; and (d) a device to remotely seal the non-hazardous area — including inlets and outlets of all ventilation systems — from the control station and from a position outside the non-hazardous ventilated area that will remain accessible during any fire that may occur within the area.