Handover & Completion · Mandatory · Completion

Commissioning Record — M&E Systems

A record of commissioning activities for mechanical and electrical systems.

Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. BSRIA / Building Regs remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.

Legal basis	BSRIA Commissioning Guides + Building Regulations Approved Document L (Conservation of Fuel and Power) + CIBSE Commissioning Codes
Status	Mandatory — commissioning of building services is a requirement of the Building Regulations and must be documented to demonstrate compliance
Prepared by	M&E Contractor (mechanical and electrical subcontractor responsible for the installation and commissioning of building services systems)
Systems covered	HVAC (heating, ventilation, and air conditioning), domestic and process water systems, electrical distribution and lighting, fire and life safety systems (fire alarm, emergency lighting, sprinklers, smoke ventilation)
Seasonal commissioning	HVAC systems require seasonal commissioning — heating mode must be commissioned in winter conditions and cooling mode in summer conditions to verify design-intent performance across the full operating range

1. Commissioning Records — Proof That Building Services Work

Commissioning records provide the documented proof that every building services system has been installed correctly, tested systematically, and is performing in accordance with the design intent. They are the quality checkpoint that sits between installation and handover, and they exist to catch installation errors, design discrepancies, and performance shortfalls before the building is occupied and the contractor leaves site.

Without commissioning records, there is no evidence that systems work as designed. The Building Regulations require that fixed building services are commissioned and that the results are documented. BSRIA and CIBSE commissioning guides set out the detailed procedures for testing each system type. The commissioning record captures the test methodology, the measured results, the design parameters, and confirmation that the system meets its specification. It is a permanent record that forms part of the O&M manual and the building logbook.

Commissioning is not the same as testing. Testing confirms that a component or circuit functions. Commissioning confirms that the entire system operates as an integrated whole, delivering the correct temperatures, flow rates, air volumes, pressures, and control responses under the conditions specified in the design. A system can pass every individual test and still fail to deliver the design intent if it has not been properly commissioned.

Commissioning must be complete before handover

Commissioning must be complete before handover — not 'nearly complete' or 'in progress'. A building handed over with incomplete commissioning records is a building where the contractor cannot demonstrate that the systems work. Incomplete commissioning is one of the most common causes of defects, disputes, and retention withholding in M&E contracts.

2. What a Commissioning Record Contains

A commissioning record must capture every piece of information needed to demonstrate that the system has been tested against its design specification and is performing correctly. The following table sets out the key elements that should be documented for each system commissioned.

Record element	What to record
Project details	Project name, address, contract reference, client name, principal contractor, and M&E contractor. The commissioning record must be clearly identifiable and traceable to the specific project and contract.
System reference	Unique system identifier, system type (e.g. LTHW heating, chilled water, supply air AHU-01), location within the building, and reference to the relevant design drawing and specification section.
Design specification	The design-intent parameters for the system — design flow rates, temperatures, pressures, air volumes, noise levels, and any other performance criteria specified by the designer. These are the benchmarks against which commissioning results are measured.
Equipment details	Manufacturer, model, serial number, and rated performance of each major item of equipment within the system (boilers, chillers, pumps, fans, AHUs, terminal units, controls components). This creates a permanent asset record.
Pre-commissioning checks	Confirmation that all pre-commissioning activities have been completed before commissioning begins: pipework flushed and cleaned, ductwork leakage tested, electrical systems energised and proved safe, control systems loaded and configured, safety devices installed and set.
Test results	The measured commissioning results for each circuit, branch, and terminal — flow rates, temperatures, pressures, air volumes, electrical readings. Results must be recorded alongside the design values so that compliance can be verified. Acceptable tolerances (typically ±10% for water, ±10% for air) must be stated.
Safety device tests	Test results for all safety devices including pressure relief valves, high-limit thermostats, frost protection, fire dampers, smoke dampers, and interlocks. Each device must be tested to confirm it operates at the correct set point and fails to a safe condition.
Controls commissioning	Verification that the building management system (BMS) and local controls are operating correctly: sensor calibration, control loop tuning, setpoint verification, time schedule programming, alarm configuration, and trend logging. The controls strategy must match the design intent.
Seasonal commissioning note	For HVAC systems, a record of whether the system has been commissioned in both heating and cooling modes. If seasonal commissioning is outstanding (e.g. heating commissioned in winter but cooling not yet tested), this must be clearly noted with a programme for return visits.
Commissioned by	Name, company, and qualifications of the commissioning engineer who carried out the commissioning. The commissioning engineer must be competent and experienced in the system type being commissioned. For critical systems, a specialist commissioning contractor may be required.
Witnessed by	Name and organisation of the person who witnessed the commissioning. Witnessing is typically carried out by the client's representative, the consulting engineer, or an independent commissioning management organisation. Witnessed commissioning provides independent verification of the results.

3. Common Mistakes

Commissioning started too late in the programme

Commissioning is frequently squeezed into the final weeks of a project because installation overruns have consumed the commissioning float. This leads to rushed commissioning, incomplete records, and systems that are handed over without proper verification. Commissioning must be programmed as a distinct activity with adequate time — it cannot be compressed without compromising quality. A realistic commissioning programme should be agreed at the start of the project and protected throughout.

No design intent document available during commissioning

The commissioning engineer cannot verify that a system meets its design intent if they do not have access to the design specification. Too often, commissioning is carried out without a clear statement of the design parameters — flow rates, temperatures, pressures, and air volumes that the system is supposed to achieve. The result is commissioning that confirms the system "works" but cannot confirm it works as designed. The design intent document must be issued to the commissioning team before commissioning begins.

Missing seasonal commissioning records

HVAC systems that operate in both heating and cooling modes cannot be fully commissioned in a single season. If the building is handed over in summer, the heating system may have been commissioned but the cooling system has not been tested under genuine cooling load conditions. The commissioning record must clearly identify which seasonal modes have been tested and which are outstanding. A programme for return visits to complete seasonal commissioning must be agreed and documented before handover.

Commissioning records not signed or witnessed

Unsigned commissioning records have no evidential value. If the records do not identify who carried out the commissioning, when it was done, and who witnessed it, there is no way to verify the results or hold anyone accountable. Every commissioning record sheet must be signed by the commissioning engineer and, where required, countersigned by the witnessing party. Electronic records must have equivalent authentication.

Commissioning records not included in the O&M manual

Commissioning records are a permanent part of the building's operational documentation. They must be included in the O&M manual so that the building operator and facilities management team have access to the baseline performance data. Without commissioning records in the O&M manual, the FM team has no reference point for how the systems were set up, what flow rates and temperatures were achieved, and what the design intent was. This makes future fault diagnosis and system optimisation significantly harder.

4. Frequently Asked Questions

What is the BSRIA commissioning process?▾

BSRIA (Building Services Research and Information Association) publishes a series of commissioning guides that set out the standard procedures for commissioning building services systems in the UK. The process follows a structured sequence: design review, installation inspection, pre-commissioning checks (flushing, cleaning, pressure testing), setting to work, regulation and balancing, performance testing, and recording of results. BSRIA guides cover specific system types including water systems (BG 2/2010), air systems (BG 3/2010), and lighting (BG 5/2010). The BSRIA process requires that commissioning is planned from the design stage, that a commissioning specification is included in the contract documents, and that commissioning results are recorded on standard record sheets that can be verified and witnessed.

What is TAB in commissioning?▾

TAB stands for Testing, Adjusting, and Balancing. It is the process of measuring the flow rates in water and air distribution systems, comparing them to the design values, and adjusting regulating valves, dampers, and fan or pump speeds to achieve the correct flow at every terminal device. TAB is a core part of HVAC commissioning. Without proper TAB, some areas of the building will be overheated or overcooled while others are underserved. TAB must be carried out by a competent commissioning engineer using calibrated instruments, and the results must be recorded on commissioning record sheets showing the design flow, measured flow, and percentage deviation for every circuit and terminal.

Is commissioning required by the Building Regulations?▾

Yes. Approved Document L (Conservation of Fuel and Power) of the Building Regulations requires that fixed building services systems are commissioned and that a commissioning notice is given to the building control body. Regulation 44 of the Building Regulations 2010 requires that the person carrying out the work must give a notice to the building control body confirming that fixed building services have been commissioned in accordance with a procedure approved by the Secretary of State. The approved procedure is set out in CIBSE Commissioning Code M. Non-domestic buildings must also comply with the requirements for commissioning certificates under Part L. Failure to commission building services is a breach of the Building Regulations.

What is the difference between commissioning and testing?▾

Testing confirms that an individual component, circuit, or device functions correctly in isolation. For example, testing a pump confirms that it runs, testing a valve confirms that it opens and closes, and testing a fire damper confirms that it closes on activation. Commissioning goes further — it confirms that the complete system operates as an integrated whole, delivering the design-intent performance under realistic operating conditions. Commissioning includes testing but also encompasses regulation, balancing, control system verification, interaction between systems, and confirmation that the system meets its specified performance criteria for temperature, flow rate, pressure, air quality, and energy consumption. A system can pass every individual test and still fail commissioning if it does not deliver the design intent as a whole.

Generate your Commissioning Record — M&E Systems on Construction Suite

Construction Suite walks you through every required section with a guided Q&A — built to BSRIA / Building Regs — and generates a professionally formatted document in minutes.

Get started free