Detection + alarm + fire doors + compartmentation + escape
Regime stack: RR(FS)O 2005 + Building Safety Act 2022 (if HRB 18m+) + HMO Standards 2018 + HMO licence conditions + HHSRS Cat 1 + 2 + BS 5839-6:2019 + BS 9251:2021 + ADB Volume 1. Detection BS 5839-6: Small HMO Grade D LD2 = mains-wired interlinked smoke alarms in escape routes + landings + ALL bedrooms + heat alarm in kitchen + lobbies + risk rooms; battery backup; annual test; cost £1,800–£3,400 per 4–6 bed. Medium-larger HMO Grade A LD1 = central control panel + addressable detection throughout (every room + cupboards + voids) + manual call points each escape level + 75dB sounder at bedhead; annual maintenance £450–£950; cost £8,500–£18,500 per 6–9 bed. Fire doors: FD30 bedrooms + risk rooms small HMO + escape route; FD60S escape route + protected stair on 3+ storey large HMO. Door spec: solid timber 44mm, intumescent + cold-smoke seals, self-closing (Briton, GEZE, Dorma) + magnetic hold-open option, FIRA-certified door + frame + intumescent + hinges + locks + viewers. FD30 £380–£680 supplied + fitted; FD60S £580–£950. Heritage challenge — original panel doors typically inadequate. Two routes: (1) full replacement matching profile (LBC sample approval); (2) intumescent retrofit (Envirograf + edge seals + drop seals — converts panel door to FD30 equivalent, LBC-preferred). Retrofit £280–£540 vs replacement £480–£950, preserves heritage. Compartmentation: 30-min between flats + bedrooms + escape; fire stopping at every service penetration (Hilti CFS, Rockwool) £45–£180 per. Common gap — penetrations in cellar/loft/risers. Protected escape route: stair + landings + lobbies to final exit; FD30/FD60S each level; no risk rooms direct onto stair (kitchen/utility = lobby buffer); emergency lighting (Hochiki, Mackwell self-test LED) each landing + final exit £180–£480 per fitting. Final exit: 800mm wide, unobstructed, openable without key, leads to place of safety.
Sprinklers + emergency lighting + FRA + costs + Builderr default
Sprinklers BS 9251:2021: mandatory in residential blocks 11m+ (ADB Vol 1 2020+) for new build; for HMO retrofit, mandatory sui generis 3+ storey in some boroughs (Tower Hamlets, Hackney, Newham routinely condition) + strongly recommended in all 3+ storey sui generis HMO. Mist (Plumis Automist Smartscan, Pegasus) £8,500–£18,500 retrofit vs traditional sprinkler £18,500–£35,000. Mist increasingly LPA-acceptable. Emergency lighting BS 5266: protected escape + landings + final exits + kitchen + risk rooms. Self-test LED £180–£480 each + 1-day install for 6–9 bed. Annual test + 3-year discharge test. FRA: RR(FS)O Article 9 + HMO licence condition. Annual by competent person (NEBOSH Fire Risk Assessor, IFE Tier 3, FRACS). £450–£950 per 6-bed HMO. Re-FRA after material change. Building Safety Act 2022 — HMO 18m+ (rare, mostly purpose-built) = HRB regime + dutyholders + Gateway 2 + 3 + BSR sign-off; see [[building-safety-act-2022-london-renovation]] + [[higher-risk-buildings-hrb-london-renovation]]. Typical scope cost by HMO size London 2026: 4-bed 2-storey: Grade D LD2 £1,800 + 4 FD30 £1,800 + compartmentation £1,200 + FRA £450 = £5,250 + 1-week programme. 6-bed 3-storey: Grade D LD2+ £2,800 + 6 FD30 £2,700 + 2 FD60S £1,400 + emergency lighting £1,800 + compartmentation £2,400 + FRA £620 = £11,720 + 2-week. 8-bed sui generis 3-storey: Grade A LD1 £14,500 + 8 FD30 £3,600 + 4 FD60S £2,800 + emergency lighting £2,400 + Mist sprinkler £14,500 + compartmentation £4,800 + fire engineer report £6,500 + FRA £950 = £50,050 + 4-week. Builderr default: appoint fire engineer (Hoare Lea, Tenos, Olsson Fire) at design for sui generis; alarm + sprinkler + FD60S coordinated with licence application; FIRAS Compartmentation-registered fire stopping (avoids retrospective BR failure); full FRA pre-occupation + annual contract. Approval rate on engineered fire-safety scheme: 95%+ (vs 65–75% on owner-DIY).
