Frequently asked questions on explosives magazine lighting

The interior of an explosives magazine is a workplace and an employer has a duty of care to provide adequate lighting. A risk assessment should be conducted to ensure there is an adequate standard of lighting, even where portable lighting (e.g. miner’s cap lamp) is used. The level of lighting should be at least 75 lumens measured at ground level.

• Natural lighting – a lower risk option that should be used wherever possible (e.g. addition of windows and skylights without compromising security)

• Artificial lighting – fixed and portable

Where fixed artificial lighting is used, it is preferable for the lighting to be installed outside the magazine and to shine inside when the doors are opened. This can be used for both surface and underground magazines.  Where artificial lighting is installed outdoors it should be of an appropriate standard to prevent the ingress of water (i.e. weatherproof).

To better reflect light, the inside of the magazine should be painted white.

If windows or skylights are fitted to the magazine to provide natural light, additional security is required. This can be in the form of steel bars and internal locked steel window shutters for the windows, and grid mesh located under the skylights.

The lights should be installed a sufficient distance from the magazine so if the lights fail or there was an electrical fault, the effects are contained and do not spread to the magazine and threaten the explosives.

Both lights and light fixtures (e.g. pole) should be out of the way of, or protected from vehicle movements, to minimise the possibility of an incident near the magazine.

The artificial lighting system needs to be adequately protected against:

• dust
• ingress of water or excessive dampness
• temperature
• vibration
• mechanical damage
• corrosion
• other influences.

Cables installed for artificial lighting in an underground mine or quarry operation must be suitably protected. In areas where such cables may be exposed to physical damage it is recommended that they be protected by a metallic covering (such as metallic conduit or armouring) or similar.

The artificial lighting circuit must be protected by an earth leakage protection device in accordance AS/NZS 3000 Electrical installations (known as the Australian/New Zealand Wiring Rules).

 

It is recommended that, as a minimum, electrical installations such as lighting fixtures and fittings, be to an IP65 rating.

Lights should be installed:

• in protected places away from vehicle movements. If vehicles are operating inside the magazine it may be necessary to fit protective guards over the lights
• away from the spray from a deluge system (for underground magazines)
• not directly above the explosives where a hot element of the light or sparks can fall on the packaging of the explosives and cause a fire.  Consideration should also be given to the type of lights used. It is better to use one that does not produce much heat (e.g. LED).

Where a fixed artificial lighting system is to be used inside an underground magazine, the lighting system should:

• be designed and installed to minimise the risk of initiation of the explosives or detonators by heat, electrical malfunction, or accidental damage to the system
• have switches for the system that are external to the magazine
• have light fixtures and fittings to comply with the requirements for dust-excluding, ignition-proof enclosures in AS/NZS 61241.1:2005  (dust ignition protection type “tD” enclosures).

Suitable permanent or fixed installation lighting should be provided at access ways to the main underground magazines.

Portable lights (e.g. flame-proof torches, miner’s cap lights) must be fit-for-purpose and not pose a danger to the explosives (e.g. do not incorporate hot elements within their design)

Portable lights with an unprotected extension cord to a power source cannot be used inside an explosives magazine.