Getting Detector Spacing Right Can Be A Bit Tricky. We've Produced This Handy Guide To Help Clear Up Some Of The Misunderstandings

Take a look at the spacing guidance below.

Smoke Detectors

Smoke detectors offer a coverage radius of 7.5m.

It's nessesary to overlap the 7.5m circles of multiple detectors so that no areas are left uncovered. This is commonly done using squares which are laid out to cover a room.

For smoke detectors each square is 10.6m wide, this means a grid of lines 10.6m by 10.6m apart with detectors placed where the lines cross.

Heat Detectors

Heat detectors offer a coverage radius of 5.3m.

Like smoke detectors it's nessesary to overlap the circles of multiple detectors so that no areas are left uncovered. This is commonly done using squares which are laid out to cover a room.

For heat detectors each square is 7.5m wide, this means a grid of lines 7.5m by 7.5m apart with detectors placed where the lines cross.

Multi Detectors

Multi detectors combine multiple technologies. If the multi detector has heat sensing capability use the heat detector spacing above. If there is no heat sensing capacity use the smoke spacing above.

Carbon Monoxide Detectors

Carbon monoxide detectors should use the smoke spacing above.

Beam Detectors

Beam detectors offer 7.5m of coverage either side of the beam. 15m in total for each beam made up of 7.5m each side of the beam path.

Apex ceilings

Where detectors are fitted in the top of an apex ceiling there is a coverage uplift.

  • Non heat detectors (Smoke/CO/Beam/Non heat Multi). In the top 600mm of the apex.
  • Heat detectors. In the top 150mm of the apex.

Increase the coverage distances mentioned above by 1% for each degree of pitch up to a maximum of 25%.

So if there is a smoke head in the top 600mm of an apex with a 12 degree pitch the radius formula will be 7.5m * 1.12 = 8.4m.

Beams may also have their coverage uplifted where the beam passes through the top 600mm of the apex.

Fire3d AI Detector Coverage Calculations

Fire3d calculates these coverage distances automatically and adjusts coverage based on the location of the detector in the room.

There are many other influences on detector coverage such as:

  • Maximum device mounting heights
  • Proximity to obstacles
  • AC & HVAC
  • Differing ceiling types
  • And more...

Fire3d AI takes all of these into account when automatically calculating coverage for detectors. Taking care of this means faster quotes and estimates and cost effective designs which are not 'Over Specified' winning you more business.

Other Fire3d AI Coverage Calculations

The AI engine also calculates coverage and complinace for many other tests to ensure BS5839 compliance.

Some of these include:

  • Risk assessment based device placements ensuring the correct coverage is in place to comply with the assessment.
  • Sounder coverage based on sounder power and ambient decibels in each room.
  • VAD coverage based on VAD classification, ambient LUX and daylight compensation in each room.
  • MCP walking distance coverage based on floorplan layout and obstructions.
  • High risk Rooms ensuring these have MCPs near.
  • Fire & Resuce search distances based on floorplan layout, zoning, obstructions and visibility.
  • And many more...

Try out Fire3D for yourself

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