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10 Year Thermally Enhanced Optical Smoke Alarm (Thermoptek) - FireAngel ST-750T

Discontinued Product

This product has been discontinued and is no longer available to buy.

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Product Overview

The ST-750T features FireAngel's groundbreaking Thermoptek technology. When the alarm detects a rise in temperature the optical smoke detection sensor becomes extra sensitive, making it able to detect fires much faster than standard optical alarms, while at the same time reducing the risk of false alarms. Powered by a sealed Panasonic lithium battery, the ultimate in battery life reliability, there is no need to change the alarm's battery for its entire 10 year lifespan.

The alarm also has a very helpful "Sleep Easy" function which allows homeowners to silence the end-of-life chirp after ten years for 8 hours to avoid being disturbed while asleep.

FireAngel's Thermoptek smoke alarms are recommended by the UK's Fire and Rescue Service.

  • Battery: Built-in, lasts the lifetime of your alarm - GUARANTEED
  • Warranty: 10 year warranty
  • Large test / silence button for no-hassle maintenance
  • Alarm Smart Silence feature helps provide maximum protection
  • Thermally enhanced sensor for quicker reactions to fire (compared to standard optical smoke alarms)
  • Reduced risk of false alarms and therefore suitable for areas adjacent to a kitchen
  • Sleep Easy™ function temporarily silences end-of-life warning chirps for 8 hours
  • Suitable for installations complying to BS 5839-6: 2019 Grade F1
  • Smoke alarm technology of choice for the UK's Fire and Rescue Service
  • Supplied with fixings; 2 x screws and 2 x rawl plugs
  • CE marked and Kitemarked to BS EN 14604
  • Please note: While the alarm features a red ring on the front, only a very small LED flashes red every 40 seconds to indicate that the alarm is working correctly.
Technical Data
Product Code FAST750T
Alternative Product Codes ST-750R, ST-750Q, ST-750T
Brand FireAngel
Battery Type

Sealed Panasonic lithium battery

Dimensions (HxDia)


Operating Temperature

+4°C to +38°C

Relative Humidity

Up to 90%

Sound Output



10 Years

Weight 0.25kg
Product Datasheets
FAQs (9)
Q. What smoke alarm should I use in a bedroom with an en suite bathroom?

It is usually recommended to install an optical smoke alarm in a bedroom. This is because optical smoke alarms are slightly quicker at detecting slow smouldering fires that can originate from upholstery type materials and over-heated wiring. Also, an optical smoke alarm would be less likely to sound a false alarm than an ionisation would, if steam/water droplets were present from the bathroom. Detectors should be installed as central to the room as possible; however for your application I would also consider the position of the en suite to make sure that the detector is not in the direct path of the joining door. This is just to try and avoid the chances of a false alarm. No detector is designed for use in bathroom areas.

Q. How do I safely dispose of my old smoke alarms?

Safelincs is signed up to Valpak's WEEE (Waste Electrical and Electronic Equipment) Distributor Take-Back Scheme (Registration ID: 7370). Private households can therefore drop off their electronic and electrical fire safety waste at their municipal recycling centre when they are purchasing new products from us. To find your nearest recycling centre, please visit

Q. How long do the batteries last in smoke alarms?

The 9V alkaline batteries last 12-18 months. Lithium batteries will usually last 5x longer than their alkaline counterparts, achieving around 5 years lifetime. Some lithium cells are also rechargeable, and when used in a mains-powered alarm may last for the entire functional lifespan of the alarm. Newer alarm models may also feature a "sealed" lithium battery. These batteries are specialist components which are designed to not be removed or need replacing by the user, and have been tested by the alarm manufacturer to ensure they last for the lifetime of the alarm.

Please Note: the actual lifetime of your batteries depends on how often the alarms are tested or activated, as sounding the alarm draws more power than when the alarms are "waiting" to detect fire. You should also read your alarm's manual to make sure you only use the recommended types and brands of batteries, as failing to follow these instructions may cause the alarm to malfunction, not alerting you in the event of a fire, and might also invalidate the warranty.

Q. Can a smoke alarm be fitted with a sticky adhesive pad in a let property?

The sticky pad is suitable for all battery operated smoke alarms. However, we cannot judge if battery alarms are suitable for your let property, as let properties usually require mains powered alarms. There is some advice to this in the governments guides to fire risk assessments.
Also see the LACoRS guide for let properties.

Q. What sort of smoke alarm system would I need to install for a HMO?

BS 5839-6 recommends that one or two storey HMOs with an individual floor area of no more than 200sqm (not the total of both floors) should have a Grade D smoke alarm system installed. Grade D refers to mains powered smoke alarms with a back up battery power supply. The alarms can be interlinked either by wire or by radio signal and the system does not require a separate fire alarm panel. For HMOs of 3 storey or higher, a Grade A panel system would need to be installed. This can cover the whole of the building, or can be used just for the communal areas with a separate Grade D system installed for the individual dwellings. For both applications, the level of cover should be a minimum of LD3 (in all escape routes) but this may change according to the fire risk assessment.

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Key Product Features

Large and easy-to-use test/silence button

Tamper-proof sealed Panasonic lithium battery

Unobtrusive small LED light indicates working status every 40 seconds

Screws and rawl plugs included for quick installation

What's Included?

Every FireAngel FAST750T is supplied with the following components.

  • 1 x FireAngel ST-750T Thermoptek alarm
  • 1 x Tamper-proof 10 year lithium battery
  • 2 x Screws and rawl plugs
  • 1 x Instruction manual

Excellent Warranty

This product is supplied with a 10 year manufacturers warranty as standard

Customer Reviews

49 customers have given this product an overall rating of 4.7 out of 5

Reviews by real customers

All of our product reviews are written by real customers that have purchased this product from us and are published without modification.

Rating: 5 / 5 Stars

Reviewed by: M G

Looks good and easy to install

Published on: 4th December 2019

Rating: 5 / 5 Stars

Reviewed by: M B

Does the job intended!

Published on: 30th May 2019

Rating: 4 / 5 Stars

Reviewed by: M K

Nice and neat looking, presume they%u2019ll do the job if required.

Published on: 17th May 2019

Rating: 5 / 5 Stars

Reviewed by: P P

Long lasting quality smoke and heat sensor alarm Something for the kitchen... Required an alarm which detected real smoke, fire heat and power lasting for 10 years - can't fault it ! No false alarms from toasting machine.

Published on: 14th May 2019

Rating: 5 / 5 Stars

Reviewed by: J C

Does what it%u2019s supposed to Clear display

Published on: 4th May 2019

Rating: 5 / 5 Stars

Reviewed by: N L

Great product, easy to install and works perfectly

Published on: 19th April 2019

Rating: 4 / 5 Stars

Reviewed by: K R

Good service and came on time .

Published on: 19th February 2019

Rating: 5 / 5 Stars

Reviewed by: P W

Simple to install and great quality product The FireAngel 10 year Thermally Enhanced Optical Smoke Alarm is an excellent product and extremely easy to install and start using.

Published on: 26th September 2018

Rating: 5 / 5 Stars

Reviewed by: J R

An excellent smoke detector Easy to fit up and is effective

Published on: 22nd July 2018

Rating: 5 / 5 Stars

Reviewed by: B R

Straightforward instructions simple as abc!!excellent product good with loud alarm

Published on: 17th July 2018

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