Type 4 Fire Risk Assessment Explained

A Type 4 FRA is commonly described as:

Common parts and flats, with destructive inspection.

It includes:

• A fire risk assessment of the common parts
• Non-destructive inspection within a sample of flats
• Destructive inspection within selected common areas
• Destructive inspection within selected flats
• Assessment of the findings in the context of the overall risk to residents

The work is completed on a sampling basis. It does not normally involve opening every wall, ceiling, floor, riser or service enclosure throughout the building.

The purpose is to investigate specific uncertainties about the building’s construction, fire separation or internal flat arrangements. The assessment should begin with a defined concern and an explanation of what the intrusive work is expected to establish.

The Type 1–4 classifications originate from recognised guidance for purpose-built blocks of flats in England and Wales. They are not four separate statutory assessment categories. The government continues to make the guidance available because it contains useful information, but describes it as no longer comprehensive for all current legal requirements.

For the wider assessment process, legal responsibilities and action planning, see Fire Risk Assessments in the UK: The Complete Guide.

A Type 3 Fire Risk Assessment covers the common parts and a sample of flats without destructive inspection.

Within sampled flats, a Type 3 assessment may consider:

• Means of escape
• Domestic smoke alarms
• Internal doors relevant to the escape route
• Alterations to the original layout
• Risks controlled by the landlord
• Conditions that could affect residents’ ability to escape

A Type 4 assessment includes those matters but also opens selected construction within the common parts and flats.

Type 4 therefore requires additional planning for access, asbestos, opening-up, reinstatement and resident disruption.

The instruction should explain why destructive investigation is required. It should not simply request Type 4 because a more intrusive assessment appears more thorough.

A Type 2 Fire Risk Assessment also includes destructive sampling, but its principal scope concerns the common parts and relevant separating construction.

Limited access to vacant flats may sometimes be required during a Type 2 assessment to inspect construction separating flats from common areas. The purpose is not normally to assess the wider means of escape and fire-safety arrangements within those flats.

Type 4 combines:

• The flat-based assessment scope of Type 3
• Intrusive investigation within the common parts
• Intrusive investigation within sampled flats

This distinction must be defined before quotations are obtained. Otherwise, one assessor may price investigation of separating construction while another includes a wider assessment of risks and escape arrangements within the flats.

Type 4 should be reserved for circumstances where evidence suggests a serious risk that cannot be assessed through Types 1, 2 or 3 alone.

Possible reasons include:

• A new owner taking control without reliable building information
• Unknown or poorly documented alterations within flats
• Evidence of widespread unauthorised building work
• Serious compartmentation concerns affecting flats and common areas
• Fire or smoke spread inconsistent with the intended building design
• Major differences between available drawings and the actual construction
• Previous sampling suggesting that defects may be widespread
• Concerns about internal escape arrangements combined with hidden construction risks
• Refurbishment affecting fire-resisting construction without reliable records
• A building whose construction and alteration history cannot be established

The recognised guidance presents Type 4 as an assessment for limited circumstances rather than a routine requirement. It gives the example of a new landlord taking control where the previous work history is unknown and there is reason to suspect serious risk to residents.

A recommendation for Type 4 should explain:

• What evidence has created concern
• Why a less intrusive assessment is insufficient
• Which risks or construction details require investigation
• Why access inside flats is necessary
• What the proposed samples are expected to establish
• How the findings will inform further action

The investigation may involve opening selected areas of:

• Walls separating flats from common areas
• Walls between adjoining flats
• Floors and ceilings
• Service risers and ducts
• Boxing around pipes and cables
• Service penetrations
• Ceiling and roof voids
• Cavity barriers
• Compartment-wall junctions
• Areas affected by refurbishment or conversion work

Samples should be chosen according to the risks being investigated rather than selected randomly.

A sampling plan may take account of:

• Different construction types
• Different phases of the building
• Known refurbishment locations
• Flats on different storeys
• Areas containing different service routes
• Locations where visible defects have been identified
• Different flat layouts
• Vacant and accessible flats
• Findings from previous surveys or opening-up work

The scope should state whether the fire risk assessor is expected to design the sampling plan or whether proposed inspection locations have already been identified.

Destructive investigation inside homes creates legal, practical and communication challenges.

Appointing an assessor does not itself create a right to enter a private flat or open its construction. The client must establish whether access can be obtained through an express lease or tenancy provision, another applicable legal right or resident consent.

The recognised guidance notes that destructive inspection within flats may only be practicable in vacant flats.

Before tendering, clients should confirm:

• Whether suitable vacant flats are available
• Which tenure types are present
• Whether access rights exist for the intended purpose
• Whether resident consent is required
• Who will issue notices and arrange appointments
• How long each flat may be affected
• Whether residents need to leave the immediate work area
• How personal possessions will be protected
• How noise, dust and waste will be controlled
• What happens if access is refused
• Whether repeat visits are included

The selected flats must also provide a defensible sample. Choosing only the easiest properties to access may leave important construction types, layouts or alteration histories unrepresented.

For wider preparation guidance, see How to Prepare for a Fire Risk Assessment.

Destructive inspection must not begin until there is adequate information about possible asbestos-containing materials in the proposed work areas.

The duty to manage asbestos applies to the common parts of multi-occupied domestic premises. Existing management information may not be sufficiently intrusive for work that will break into walls, ceilings or other concealed construction.

Where the proposed openings could disturb materials that have not been adequately assessed, a targeted refurbishment survey may be required before work begins. HSE guidance states that work should not proceed until sufficient asbestos information is available.

The client should provide:

• The asbestos register
• The asbestos management plan
• Existing management and refurbishment surveys
• Information covering each proposed opening
• Records of previous asbestos removal
• Plans showing known or presumed asbestos materials

The tender should state:

• Who reviews the asbestos information
• Who arranges additional surveys
• Who authorises each opening
• Who stops the work if unexpected materials are found
• How asbestos-related delays or revised sample locations will be handled

The assessor will not necessarily carry out the physical opening work.

A competent contractor will normally be required to:

• Protect the work area
• Locate concealed services
• Open the selected construction
• Enable the assessor to inspect the exposed area
• Install temporary protection where required
• Restore fire-resisting construction
• Complete permanent making good
• Remove debris and leave the area safe

Responsibility for these activities must be stated clearly.

The contract should identify whether:

• The opening-up contractor is appointed directly by the client
• The assessor appoints or manages the contractor
• Contractor costs are included in the assessment quotation
• Additional samples can be authorised during the visit
• Additional work requires a written instruction
• Decoration is included after fire-resisting construction is restored

A cosmetic patch is not sufficient where a fire-resisting wall, floor or ceiling has been opened. The reinstatement must restore the intended fire and smoke resistance.

A Type 4 FRA and a compartmentation survey can overlap, but they do not necessarily provide the same service.

A Type 4 assessment considers overall risk to life across the common parts and sampled flats. Intrusive samples are used to investigate relevant construction concerns.

A compartmentation survey focuses more specifically on the continuity and condition of fire-resisting construction. It may inspect more locations and produce a detailed defect register suitable for remedial procurement.

Before commissioning intrusive work, clients should decide whether the objective is to:

• Assess overall fire risk
• Investigate a defined structural concern
• Determine whether defects are widespread
• Produce a comprehensive defect schedule
• Prepare a contractor-ready remedial specification

See Fire Risk Assessment vs Compartmentation Survey for a detailed comparison.

Where a broader specialist investigation is required, the client may also need to appoint a provider through the Compartmentation Surveys service cluster.

The final report should explain what was investigated, what was found and what remains uncertain.

It should include:

• The reason Type 4 was selected
• The evidence reviewed before inspection
• The common areas and flats assessed
• The sampling strategy
• Every opening location
• Areas that could not be opened
• Photographs before, during and after opening
• Construction details observed
• Confirmed defects
• Findings affecting escape within flats
• Limitations of the sample
• Implications for similar uninspected areas
• Immediate or interim precautions
• Recommendations for further surveys or remedial work

The report should distinguish confirmed findings from inferences.

One defective sample does not prove that every similar area is defective. Equally, satisfactory samples do not guarantee that concealed construction throughout the building is adequate.

A Type 4 assessment may identify urgent precautions, further investigation or significant remedial work.

The client should establish:

• Who receives urgent findings
• Who decides whether interim measures are required
• Who owns each action
• Whether further samples are needed
• Whether a wider specialist survey is required
• What evidence will demonstrate completion
• Whether the FRA must be reviewed after work is completed

For guidance on prioritising and managing the recommendations, see Understanding a Fire Risk Assessment Action Plan.

The wider journey from report receipt to scoping and procuring remedial work is covered in What Happens After a Fire Risk Assessment.

Type 4 requires an assessor with experience of residential fire risk, flat escape arrangements and intrusive construction investigation.

When comparing Fire Risk Assessment Companies, examine:

• Experience of purpose-built residential blocks
• Previous Type 3 and Type 4 assessments
• Knowledge of compartmentation and fire stopping
• Ability to design defensible sampling strategies
• Experience working within occupied or vacant flats
• Understanding of asbestos and opening-up controls
• Ability to interpret plans and refurbishment records
• Technical-review arrangements
• Professional indemnity insurance
• The named assessor who will attend

The opening-up contractor must also be competent to expose and reinstate the relevant construction.

A structured tender should identify:

• Building address, height, storeys and number of flats
• Confirmation that the building is purpose-built
• Evacuation strategy
• Ownership and tenure information
• Evidence justifying Type 4
• Previous FRA and survey findings
• Available plans and refurbishment records
• Sampling objectives
• Expected number and types of flats
• Vacant-flat availability
• Access and consent arrangements
• Asbestos information
• Opening-up responsibilities
• Temporary protection and reinstatement standards
• Required photographs and location records
• Process for authorising additional samples
• Report format and action priorities
• Named-assessor requirements
• Programme, pricing assumptions and VAT

Bidders should explain their proposed samples, expected disruption, contractor arrangements and approach to inaccessible locations.

For a complete specification checklist, see What Clients Should Include in a Fire Risk Assessment Tender Pack.

For the wider procurement process, see How Commercial Fire Protection Tendering Works and Fire Protection Tenders in the UK: The Complete Guide.

Common mistakes include:

• Treating Type 4 as automatically better than other assessment types
• Commissioning intrusive work without a defined concern
• Failing to establish access rights before tendering
• Assuming occupied flats can be opened without significant coordination
• Selecting samples only according to convenient access
• Proceeding without sufficient asbestos information
• Failing to appoint an opening-up contractor
• Leaving reinstatement outside every party’s scope
• Comparing quotations based on different sample sizes
• Assuming sampled findings represent every flat
• Confusing Type 4 with a comprehensive compartmentation survey
• Failing to plan for serious defects discovered during opening
• Tendering major remedial work from insufficient evidence

A proportionate Type 4 assessment begins with a defined risk question and ends with evidence that supports a clear decision about precautions, further investigation or remedial work.

For clients and managing organisations

Use Fire Risk Assessment Companies to compare providers with relevant residential and intrusive-assessment experience.

Give every bidder the same evidence, sampling objectives, access information and reinstatement requirements so methodology and price can be compared consistently.

For fire risk assessors and consultancies

View Fire Risk Assessment Tenders for opportunities with defined flat-access and intrusive-inspection requirements.

A strong submission should explain why the proposed samples are appropriate, how opening-up will be controlled and how findings and limitations will be reported.

What is a Type 4 fire risk assessment?

It is a destructive assessment covering the common parts and a sample of flats within a purpose-built block. It combines the flat-based scope of Type 3 with intrusive inspection.

Is a Type 4 FRA required for every high-rise block?

No. Height alone does not establish that Type 4 is required. There should be evidence justifying destructive inspection within both the common areas and flats.

Can Type 4 work be completed in occupied flats?

It may be possible, but vacant flats are often more practical. Access rights, consent, asbestos, disruption and reinstatement must be resolved before work begins.

Is Type 4 the same as a compartmentation survey?

No. Type 4 uses destructive sampling as part of an overall life-safety assessment. A broader compartmentation survey may still be needed to identify and schedule hidden defects throughout the building.

Who opens and repairs the walls or ceilings?

A competent contractor will normally create the openings and reinstate the construction. The tender must state whether that contractor is appointed by the client or included within the assessor’s service.