I.S. 3218:2024 — Domestic Dwellings

Minimum requirements for domestic FDAS

• Baseline category: For dwelling houses up to three storeys and for individual apartments/maisonettes, the minimum level of protection is Category LD2.
• When LD1 is required: Use Category LD1 where any of the following apply:
  • the individual dwelling’s floor area exceeds ~200 m²;
  • the dwelling is higher than three storeys; or
  • the fire risk assessment identifies features warranting higher coverage.
    These thresholds and the risk‑based escalation are carried forward in the 2024 edition.

Grades (domestic self‑contained systems)

• Grade D (mains‑powered with integral standby) and Grade F (sealed long‑life battery) remain the relevant grades for domestic self‑contained installations under I.S. 3218:2024. Interconnection may be wired or RF. The system grade and category should be determined by a competent person via risk assessment.

Remote control / hard‑to‑access locations

• Where the risk assessment places detectors in attics/roof voids or other hard‑to‑reach areas, provide remote test/location/silence functionality so the user can safely operate the alarms from an accessible point.
• Interconnection may be by radio (RF) or cable. Where domestic FDAS needs fall outside self‑contained Grade D/F scope (e.g., complex layouts, enhanced monitoring), a monitored Grade A/B/C system may be specified as appropriate—based on risk and competent design.

Audibility

• The fire alarm signal should achieve ≥ 85 dB(A) at the doorway of each bedroom (door open), regardless of the room of fire origin.
• Where occupants have hearing impairments or other vulnerabilities, provide suitable visual/tactile alerting (e.g., strobes, vibrating pads) and consider higher sound pressure where needed.
• Consider audibility on external terraces/balconies where people might be trapped by fire or smoke.

Wiring / interconnection

• For interconnecting Grade D devices, standard domestic mains wiring cables are acceptable; they should be readily distinguishable from other mains cables (e.g., colour coding) to aid identification.
• Interconnection may be RF or hard‑wired; ensure reliability and compatibility are addressed in the design/commissioning records.

Routine testing and servicing (domestic)

• User testing: Test alarms at least monthly in accordance with the manufacturer’s instructions (the 2024 edition aligns routine user tests to a monthly cadence; weekly is not required for domestic self‑contained systems).
• Cleaning/maintenance: Clean devices periodically per manufacturer guidance.
• Certificates & records: On completion/alteration, issue the I.S. 3218:2024 Annex B confirmations (Design, Installation, Commissioning, Acceptance). For ongoing maintenance, keep the Annex F Service & Testing schedule and logbook up to date.

Existing multi‑occupancy residential buildings

• Where an existing multiple‑occupancy residential building (with inadequate or no FDAS) is being brought toward compliance, a competent person may—subject to risk assessment and consultation with the Local Authority Fire Service—specify radio‑interconnected smoke and heat alarms with sealed 10‑year batteries within individual dwellings as an interim/upgrade measure.
• The location and performance of such devices must still meet the domestic requirements of I.S. 3218:2024 for the dwelling units.
• Common (communal) areas: Provide a Category L3X system (or higher where risk warrants) designed, installed and maintained to I.S. 3218:2024.

Existing dwelling houses (individual)

• For existing individual dwellings (built prior to mandatory mains‑powered interconnected alarms) with inadequate detection, radio‑interconnected smoke and heat alarms with sealed 10‑year batteries may be employed to achieve compliant coverage, provided placement, audibility and interconnection meet the 2024 requirements and the choice is justified by a risk assessment.