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Mains Powered Smoke Alarms & Heat Alarms with Alkaline Back-up Battery - Firehawk BB Series

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From: £14.22 inc VAT
£11.85 ex VAT
Product Overview

The FH250BB optical smoke alarms and FH450BB heat alarms from Firehawk are mains-powered alarms with hardwire interlink, allowing up to 15 compatible alarms in the house to sound a warning to occupants when one detects a possible fire. These models feature replaceable AAA alkaline back-up batteries to ensure continued fire detection during a power cut, or if mains-power is turned off for other reasons like decorating or a blown light bulb. The unique Fast-Fix mounting base design allows alarms to be easily removed for cleaning and replacing batteries without needing to cut the power or worry about wiring, and the alarms will chirp an "end of life" warning (which can be silenced overnight) when the whole unit needs replacing after 10 years.

  • 230V mains powered with alkaline battery backup
  • 3 x AAA alkaline battery backup (included)
  • 6 year manufacturer's warranty
  • Available in two versions:
    • FH250BB optical smoke alarm – suitable for most rooms including hallways, landings, living rooms, and bedrooms
    • FH450BB heat alarm – suitable for rooms likely to have steam, dust, or fumes like kitchens and garages
  • Also available with lithium back-up batteries that last the full 10 year life of the alarms
  • Fast-Fix design for quick installation using Push-Fit connectors
  • Up to 15 Firehawk mains-powered smoke and heat alarms can interlink in one system
  • Advanced sensor technology to ensure quick detection of fires and reduced false alarms
  • End of life warning chirp can be silenced up to 10 hours
  • Combined large test and silence button for ease of maintenance
  • Suitable for installations complying to BS 5839-6 Grade D2
  • CE marked and certified to EN 14604: 2005 (smoke alarm) / Kitemarked to BS 5446-2: 2003 (heat alarm)
  • This alarm is also suitable for the updated 2022 Scottish legislation for fire alarms in homes

The table below shows all alarms which can interlink via cable with the Firehawk FH250BB and FH450BB mains powered smoke & heat alarms.

Model Description Interlink
FH250BB Mains Powered Optical Smoke Alarm with Alkaline Battery Backup Hardwire
FH450BB Mains Powered Heat Alarm with Alkaline Battery Backup Hardwire
FH250RB Mains Powered Optical Smoke Alarm with Sealed Lithium Battery Backup Hardwire
FH450RB Mains Powered Heat Alarm with Sealed Lithium Battery Backup Hardwire

Technical Data
Product Code
FH250BB Optical Smoke Alarm FIFH250BB
FH450BB Heat Alarm FIFH450BB
Brand Firehawk
Back-Up Battery

3 x AAA Alkaline Replaceable Batteries

Dimensions (HxDia)

FH250BB Smoke: 55 x 113mm

FH450BB Heat: 69 x 113mm

Operating Temperature

0°C to 40°C

Relative Humidity

< 85%

Sound Output


Storage Temperature

5°C to 30°C


FIFH250BB: 0.25kg

FIFH450BB: 0.21kg

Product Datasheets
FAQs (5)
Q. What type of smoke alarm do I need?

We recommend using an optical smoke alarm in hallways, living rooms, dining rooms and bedrooms, as they are good at detecting smouldering fires from soft furnishings and are less likely to be set off by cooking fumes from a connected kitchen.

Ionisation alarms are recommended for landings as they are designed to react quickly to fast flaming fires.

Heat alarms are recommended for kitchens and garages as they do not sound false alarms from cooking fumes, vehicle fumes or steam.

Q. Why do your mains powered alarms have batteries?

All our mains powered alarms have a battery backup because, although mains powered alarms without this option do exist (BS5839 part 6 grade E), we regard them as far too dangerous. This is because a lot of fires are caused by electrical faults which would leave the building unprotected against fire if the smoke alarms had no backup battery. With our mains powered alarms you will always be protected.

Q. Can I put my smoke alarm on the wall, or must it be mounted on the ceiling?

The best location to install your smoke alarm is in the centre of the ceiling rather than on the wall.

During a fire, smoke initially rises and then spreads horizontally. Placing the smoke alarm in the centre of your ceiling means that it is closest to all four points of your room. This ensures that you receive the earliest possible warning of a fire.

For more information, read our guide to positioning your smoke alarm and guide to which smoke alarms are best for each room.

Q. Do you need an electrician to connect mains powered smoke alarms?

It is necessary that an electrician installs mains powered smoke alarms.

Q. Which smoke, heat & CO alarms are suitable for the 2022 Scottish regulations?

From February 2022 all homes in Scotland must be fitted with interlinking smoke and heat alarms. In addition carbon monoxide alarms are required if there is a carbon-fuelled appliance or flue. View our list of alarms suitable for the Scottish regulations.

Key Product Features

Fast-Fix mounting base design for quick, easy installation

3x AAA alkaline battery backup and fixing pack with each alarm

Alarms can be removed quickly to easily replace the batteries

Combined large test and silence button for ease of maintenance

Pricing & Availability

Model Stock Price
FH250BB Optical Smoke Alarm
Product Code: FIFH250BB
Stock Level:
More than 20 in stock Expected dispatch: 27th Jun

£14.22 inc VAT

£11.85 ex VAT

FH450BB Heat Alarm
Product Code: FIFH450BB
Stock Level:
5 in stock Expected dispatch: 27th Jun

£15.48 inc VAT

£12.90 ex VAT

Delivery Options

The following delivery options are available on this product.

Economy Delivery

£4.99 inc VAT - Orders will be delivered in 3-5 working days with Evri by Hermes

Express Delivery

£8.10 inc VAT - Orders will be delivered in 1-2 working days with Evri by Hermes

Looking for more information?

If you have any questions or would like more information about this product you can ask one of our specialists.

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