Hot Works
permit to work

Welding, cutting, grinding, brazing, soldering, or any work producing heat, sparks, or flame.

These are the precautions the issuer confirms before signing. Each one says what good looks like, when it passes, the regulation it rests on and how it usually fails. Critical precautions are marked: if one cannot be confirmed, the permit is not issued.

Precautions before issue

1. 1.

   Area inspected and combustibles cleared/protected

   Critical: a fail stops the work
   What to look forA clear 10m radius around the work point with all loose combustibles (paper, cardboard, timber off-cuts, oily rags, plastic sheeting, gas cylinders, fuel cans) physically removed. Where combustibles cannot be moved (e.g. structural timber, insulation, flammable cladding) they must be covered with proprietary fire blankets, welding curtains, or non-combustible boards (mineral wool, gypsum), not just a tarp. Floor seals, deck penetrations, conveyor openings and cable trays within 10m are sealed with intumescent foam or fire blanket to stop sparks falling to lower levels.
   Acceptable when10m clear radius minimum (Joint Code of Practice / FPA 6th edition); 15m where work is at height with sparks falling. Welding curtains rated to BS EN ISO 25980 (1500 g/m² minimum). All fuel sources >10m or in a dedicated fuel store. Where 10m cannot be achieved the area must be wetted down and a second fire watcher posted at the spark fall point.
   StandardRegulatory Reform (Fire Safety) Order 2005 art. 8-22. Joint Code of Practice on the Protection from Fire of Construction Sites (9th edition, 2022). HSG168 Fire safety in construction. BS EN ISO 25980 welding curtains.
   Common defects10m radius measured loosely, gas bottle or solvent drum within 5m unnoticedTarp used as a spark blanket, melts and ignites at 200 degCFloor penetration / cable tray under work point not sealed, sparks fall onto lower floor combustiblesInsulation behind ductwork or wall lining not identified, smouldering ignition discovered hours laterAdjacent void (suspended ceiling, riser shaft) not opened up and inspected before works begin
2. 2.

   Fire extinguisher within 2m of works
   What to look forAppropriate-class extinguisher placed within arm-reach (max 2m) of the work point, not at the entrance to the area or behind stacked materials. Pressure gauge needle in the green band, tamper-seal intact, last service tag in date (annual service plus 5-yearly extended service to BS 5306-3). Operator has been shown the PIN procedure and knows the class of fire it tackles.
   Acceptable whenMinimum 2 x 9-litre water or 6L AFFF foam for class A combustibles. CO2 (5kg) for any electrical risk. ABC dry powder NOT permitted indoors as primary cover (visibility loss). Extinguisher serviced within last 12 months and pressure-tested within last 5 years (BS 5306-3). Within 2m of the spark/flame point at all times.
   StandardRegulatory Reform (Fire Safety) Order 2005. BS 5306-3:2017 commissioning and maintenance of fire extinguishers. BS 5306-8:2012 selection and positioning. Joint Code of Practice 9th edition.
   Common defectsSingle 2kg CO2 only, inadequate for class A combustibles in the areaExtinguisher service tag overdue (>12 months), pressure cannot be relied uponSited at door rather than at work point, operator has to traverse fire to reach itTamper seal broken from previous use, never rechargedNo-one on the team trained to operate it (no PIN drill given)
3. 3.

   Fire blankets available and in position
   What to look forWelding/spark blankets sized for the work, BS EN ISO 25980 rated, draped over combustibles below and around the spark fall zone. Where work is overhead, secondary blanket or non-combustible drop sheet positioned to catch slag below. Blanket free from holes, char damage, or oil contamination. Personnel know how to deploy a personal fire blanket (small kitchen-style) if PPE catches.
   Acceptable whenWelding curtains/blankets to BS EN ISO 25980 grade A (1500 g/m² minimum, 1000 degC contact rating). Personal fire blanket BS EN 1869:2019 (1.2m x 1.2m minimum, kitemarked). Positioned to catch all spark/slag fall, not just laid flat near work point.
   StandardBS EN ISO 25980 welding curtains/blankets. BS EN 1869:2019 fire blankets. Joint Code of Practice 9th edition. HSG168.
   Common defectsGeneric builders tarp used instead of rated welding blanket, ignitesBlanket has burn-through holes from previous use, sparks pass throughBlanket positioned beside work point not under spark fall trajectoryNo drop-sheet under elevated work, slag falls 5m onto deck combustibles
4. 4.

   Fire watcher appointed and briefed

   Critical: a fail stops the work
   What to look forA named, dedicated fire watcher whose only job is to watch for fire, not the welder, not the labourer, not someone "keeping an eye on it" between other tasks. Briefed on raise-the-alarm procedure, extinguisher operation, the 60-minute (or 120-minute insurer) post-work watch, and the 360-degree sight line to all adjacent voids/floors. On site for the duration of works AND for the full post-work watch period.
   Acceptable whenOne dedicated fire watcher per work point. Trained in extinguisher use (current within 12 months). Stays in position during works AND for minimum 60 minutes post-work (Joint Code of Practice). Where fire risk is elevated or insurer requires, 120-minute post-work watch. Fire watcher has direct comms to site supervisor and means to raise the building alarm.
   StandardRegulatory Reform (Fire Safety) Order 2005. Joint Code of Practice on the Protection from Fire on Construction Sites (9th ed). HSG168.
   Common defectsWelder doubles as fire watcher, physically cannot watch and weld simultaneouslyFire watcher leaves during the 60-minute post-work period, smouldering ignition develops unattendedSingle watcher cannot see all faces of the structure (e.g. far side of stud wall, floor below)Watcher untrained in extinguisher operationNo means to raise the wider building alarm, local building evacuation delayed
5. 5.

   Smoke/heat detectors locally isolated (with permit)

   Critical: a fail stops the work
   What to look forA formal detector isolation permit issued by the building responsible person / fire alarm engineer, not just bags taped over heads. Only the specific detectors covering the work zone are isolated, not the whole zone or the whole building. A clear log of which heads are isolated, when isolation began, expected restoration time, and a named person responsible for restoring. Isolation NEVER spans an unattended period.
   Acceptable whenDetector isolation by competent fire alarm engineer in accordance with BS 5839-1. Isolation log kept. Isolated detectors restored and tested before site is left unattended at end of shift. Manual call points remain in service. Building responsible person and on-site security informed in writing.
   StandardBS 5839-1:2017 fire detection and fire alarm systems for buildings. Regulatory Reform (Fire Safety) Order 2005 art. 17 (maintenance). Joint Code of Practice 9th ed.
   Common defectsPlastic bag taped over detector, not formally isolated, alarm panel shows fault, ignoredWhole zone isolated when only one detector needed, fire elsewhere goes undetectedDetector left isolated overnight, building unprotected during unattended periodNo isolation log kept, restoration forgotten next morningManual call points also disabled in error
6. 6.

   Sprinkler system considerations addressed
   What to look forFor occupied buildings with active sprinkler systems: localised sprinkler heads NOT isolated unless absolutely essential, and only with a formal sprinkler impairment permit signed by the responsible person and notified to the insurer. Where heads are isolated, a fire watch + portable fire-fighting capacity is doubled and isolation time is minimised. Sprinkler heat-shielded if work is close enough to trip the bulb (<1m).
   Acceptable whenSprinkler impairment notified to insurer (most policies require 24-48 hours pre-notification). Impairment durations <8 hours where possible. Heat shielding where work is within 1m of a sprinkler head (welding spark/heat will burst the 68 degC bulb prematurely). Restoration tested before leaving site.
   StandardBS EN 12845:2015 fixed firefighting systems (sprinklers). LPC Rules for Automatic Sprinkler Installations (TB203 impairment). Insurer policy conditions.
   Common defectsSprinkler isolated without insurer notification, policy voided in event of lossWelding within 30cm of a pendant head, 68 degC bulb bursts mid-work, area floodsWhole floor sprinkler valve closed when only local heads needed isolationRestoration not tested, system left in fault condition overnight
7. 7.

   Adjacent areas checked above/below/behind
   What to look forPhysical inspection of the floor below, the floor above, and any cavity behind the work point (stud wall, riser shaft, suspended ceiling, ductwork insulation, cable tray), opened up and looked into, not just assumed. Where the work is on a steel section, the heat conducts through the section and can ignite combustibles in contact 5-10m away. Insulation in contact with hot steelwork is the classic latent ignition source.
   Acceptable whenAll voids within 10m of work point physically opened/inspected before works. Steel sections traced and any combustible in contact with the section (insulation, timber, cable jacket) removed or wetted. Floor below has fire watcher posted where sparks may fall through penetrations.
   StandardJoint Code of Practice 9th edition s.7. HSG168. RR(FS)O 2005.
   Common defectsWelder cuts a beam that runs through a stud wall, insulation in contact ignites 4 hours laterSuspended ceiling void above not opened, falling slag lands on cable bundleFloor below not patrolled, penetration around riser unnoticedAdjacent room locked, assumed empty, actually contained solvent store
8. 8.

   Appropriate PPE available (welding mask, gauntlets, apron)
   What to look forAuto-darkening welding helmet to EN 379 (shade 9-13 selectable for the process and current). Leather gauntlets to EN 12477 type A (welder), not type B (light duty). Leather apron and spats covering boot tops. Long-sleeve flame-retardant overalls (EN ISO 11611 class 2 minimum for MMA, MIG). Boots to EN ISO 20345 with metatarsal guard for heavy work. No synthetic clothing under FR layer (melts to skin).
   Acceptable whenHelmet EN 379. Gauntlets EN 12477 type A. Overalls EN ISO 11611 class 1 for low spatter (e.g. light gas welding) or class 2 for high spatter (MMA, MIG, plasma). Boots EN ISO 20345 S3. Eye protection under helmet rated to EN 166 grade B for grinding. RPE if galvanised steel, paint, lead, cadmium being heated.
   StandardEN 379 welding filters. EN 12477 welder gauntlets. EN ISO 11611 protective clothing for welding. EN ISO 20345 safety footwear. PPE Regs 2002.
   Common defectsType B (light duty) gloves used for MMA welding, splatter burn-throughCotton T-shirt under overalls instead of FR layer, sleeve catches under cuffAuto-darkening helmet battery flat, shade fails on first arc strike, eye flashNo RPE when cutting galvanised steel, metal fume feverTrouser turn-ups catching slag at boot top
9. 9.

   Ventilation adequate for fumes
   What to look forLocal exhaust ventilation (on-torch fume extraction or portable LEV unit) at the point of fume generation, not just general room ventilation. Confined or semi-confined spaces have forced air supply AND extract. Operator stands upwind / out of the visible plume. RPE (FFP3 or powered air respirator) used as a backup, not as the primary control. LEV thoroughly examined every 14 months (TExT to COSHH reg 9).
   Acceptable whenLEV captures fume at source, visible smoke drawn into hood, none escaping to breathing zone. Air change rate sized for the work (typical: 12-30 air changes per hour for hot works). RPE: FFP3 minimum for steel fume, APF 20 powered respirator for stainless / chrome / nickel / manganese. Welding fume reclassified Group 1 carcinogen (IARC 2017), RPE now mandatory for ALL indoor welding (HSE bulletin Feb 2019).
   StandardCOSHH 2002 reg 7 + 9. EH40/2005 Workplace Exposure Limits. HSE bulletin Feb 2019, welding fume control measures. INDG408 Welding fumes. BS EN ISO 21904 LEV for welding.
   Common defectsWeld fume rising to face, operator chasing the cloud with their visorNo RPE for indoor welding (post-2019 HSE position), non-compliantLEV TExT certificate >14 months old, duty extraction performance unknownPowered respirator battery flat, operator removes hood mid-taskGalvanised / stainless / cadmium-plated steel cut without specific RPE for the metal fume
10. 10.

    Post-work fire watch period defined (minimum 60 minutes)

    Critical: a fail stops the work
    What to look forFire watcher remains on station for a defined period after the last spark, minimum 60 minutes per the Joint Code of Practice, extended to 120 minutes where the work is in a high-risk environment (heritage timber, complex cavities, insulation in contact with steel, building unoccupied overnight). Walk-around inspection of all areas where heat could have transferred (above, below, behind, along steel sections). Permit explicitly states the watch end time. Detectors restored and tested before site is left.
    Acceptable when60 minutes minimum (Joint Code of Practice). 120 minutes for hot works in roof voids, on insulated panel, near combustible cladding, on heritage structures, or where insurer policy demands. Final walk-around with thermal imaging camera (where available) before sign-off. Detectors restored, alarm system tested, security informed before leaving.
    StandardJoint Code of Practice on the Protection from Fire on Construction Sites (9th ed) s.9. RR(FS)O 2005. HSG168. Many UK insurers (e.g. RSA, Aviva, AXA) require 120 minutes, check policy schedule.
    Common defectsFire watcher leaves with the welder, no post-work watch at all60-minute watch from start of work, not from cessation, actual smouldering window unwatchedWatch period 60 minutes when insurer policy demands 120, policy voidedDetectors not restored before site closed, building unprotected overnightNo thermal sweep of cavities, latent ignition in cable tray ignites at 03:00Smouldering ignition in mineral wool 4-5 hours later, outside the 60-minute window but a known mechanism for hot-work fires

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