PFEER regulations (1995) – for offshore installations for the Prevention of Fire and Explosion and Emergency Response. They came into force 20th June 1995. They are law in the UK.

In summary these regulations state the person or company responsible for an installation is also responsible for protecting persons on the installation from fire and explosion and securing effective emergency response.

This implies many requirements, one of them being that a suitable means of informing people on the installation of certain alarm states (with sounders and or speech / PA systems, beacons may also be required to supplement the audible signals). There must be provision for three types of alarm on the installation / platform, 

1. Prepare for evacuation of installation / platform
2. Toxic gas -  (also where necessary red beacon / strobe)
3. Other cases for alarm (Fire) (also where necessary yellow beacon / strobe)

NOTE: these tones are indicated on the tables on the BEx data sheets.

The actual tone patterns are specified in UKOOA (UK Offshore Operators Association Limited) – guide lines for safety related telecommunication systems on normally attended fixed offshore installations.

In summary it states,

Prepare for evacuation of installation / platform: Continuous constant amplitude with varying frequency 1200Hz to 500Hz over 1 second then repeated.

Toxic gas : Constant 1000Hz  (also where necessary red beacon / strobe).

Other cases for alarm:
General Alarm (Fire): 1000Hz, 1 second on, 1 second off (also where necessary yellow beacon / strobe)

The specifications for beacons are as follows:
Flash Rate: between 60 and 180 flashes per minute.
Luminous intensity: at least 300 candelas but no greater than 400 candelas excluding the attenuation of the coloured filters.
Filter Attenuation: YELLOW – less than 15% RED – less than 85%

NOTE: for xenon beacons the flash rate should be near the low end of the range specified.