What Is Commissioning?

Commissioning is the systematic process of testing, adjusting, and verifying mechanical systems — particularly air and water systems — to confirm that:

• They are installed correctly
• Operate according to the design intent
• Meet performance specifications
• Comply with regulations and industry standards

It includes both pre-commissioning (setup and cleaning) and functional commissioning (final balancing and verification).

Air Commissioning Services Overview

• Ventilation Systems: Supply and extract air systems
• Air Conditioning: Ducted FCUs, AHUs, VRF/VRV systems
• Air Handling Units (AHUs): Fans, filters, dampers
• Terminal Devices: Grilles, diffusers, VAV boxes
• Smoke Control/Ventilation: Stairwell pressurisation systems

Process Steps

Pre-Commissioning Checks

• Visual inspection for correct installation
• Leak and integrity testing of ductwork (as per DW/143)
• Air Volume Testing
• Measure airflow rates (l/s or m³/h) at diffusers and grilles using anemometers or balometers.
• Confirm design air changes per hour (ACH) or specific ventilation rates per CIBSE Guide B.
• Air Balancing
• Adjust dampers and controls to ensure proportional airflow across all terminals.
• Balance supply vs. extract air to maintain pressure regimes.
• Pressure Testing
• Test static and differential pressures in ducts and air handling spaces (e.g., cleanrooms, labs).
• Temperature and IAQ Verification
• Confirm supply air temperature, humidity, and filter performance.
• Validate compliance with BS EN 16798 and Building Regulations Part F.
• Noise/Vibration Testing
• Check fan and ductborne noise complies with project acoustic specifications (NR/NRC levels).

Water Commissioning Services Overview

• LTHW and CHW systems (Low-Temperature Hot Water / Chilled Water)
• Domestic hot and cold water systems
• Closed loop systems: Heating and cooling circuits
• Open systems: Potable and process water systems
• Boilers, calorifiers, pumps, and expansion vessels

Process Steps

• Pre-Commissioning Cleaning
• Flushing and chemical cleaning (BSRIA BG29) to remove debris, oils, and biofilms.
• Use of biocides, scale inhibitors, and corrosion protection.
• Hydraulic Testing
• Leak testing of pipework and pressure vessels.
• Flow testing and flushing in accordance with CIBSE CP1.
• Flow and Temperature Balancing
• Adjust balancing valves to ensure uniform flow in LTHW/CHW systems.
• Balance domestic water systems to prevent scalding, Legionella risk, and pressure drops.
• Pump Setup and Commissioning
• Configure variable speed drives (VSDs)
• Set duty/standby operation where applicable.
• Water Quality Testing
• Legionella risk management per ACoP L8 / HSG274
• pH, hardness, conductivity, TDS checks (especially in closed systems)
• Thermal Checks
• Confirm hot water ≥60°C at outlets
• Cold water ≤20°C at sentinel points

Commissioning Deliverables

• Commissioning Plan (developed early, often by a Commissioning Manager)
• Test Certificates for airflow, balancing, water quality, etc.
• Flow Diagrams & Marked Drawings showing valve positions and test points
• O&M Manuals with commissioning data and logs
• Seasonal Commissioning Plan (for systems that vary over seasons)
• Witnessed Commissioning Reports signed by consultants or clients
• Integration with Building Performance

Commissioning supports:

• BREEAM credits (e.g., Hea 02 for IAQ)
• TM31 energy logbook development
• Post-Occupancy Evaluation (POE)
• Soft landings framework for smooth handover

Maintenance & Recommissioning

Seasonal commissioning checks once occupancy and seasons shift.

• Rebalancing after refits or occupancy changes.
• Annual water testing and HVAC system adjustments as part of PPM.

What is HVAC Validation?

HVAC (Heating, Ventilation, and Air Conditioning) validation is the formal process of testing and verifying that a building’s HVAC systems perform according to the design specifications, regulatory standards, and operational requirements. This process is especially critical in sectors such as healthcare, pharmaceuticals, laboratories, cleanrooms, and high-performance commercial environments.

HVAC validation goes beyond standard commissioning. It ensures that all systems meet specified environmental parameters such as airflow, air changes per hour, filtration efficiency, temperature control, pressure regimes, and cleanliness levels. Validation is often a legal, clinical, or regulatory requirement.

Where is HVAC Validation Required?

HVAC validation is required in a wide range of sectors, including healthcare facilities, cleanrooms, pharmaceutical manufacturing (regulated by MHRA or EU GMP), laboratory and research environments, and commercial buildings aiming for environmental certification or operating critical environments like server rooms.

In healthcare, HVAC validation is governed by HTM 03-01, which sets strict standards for ventilation in operating theatres, isolation rooms, and sterile services.

Stages of HVAC Validation

1. Design Review and Documentation Verification

This step involves reviewing the system's design documentation, drawings, zoning plans, and specifications. The purpose is to ensure that the intended system design meets applicable standards such as HTM 03-01, ISO 14644-1 (for cleanrooms), EU GMP Annex 1 (for pharmaceuticals), or BS EN 12599.

2. Installation Qualification (IQ)

Installation checks verify that HVAC components have been installed correctly. This includes inspection of ductwork, terminal devices (e.g. diffusers), filtration units (including HEPA filters), AHUs, FCUs, dampers, fans, sensors, and control systems. All installations are checked against approved design documents.

3. Operational Qualification (OQ)

OQ testing confirms that the system functions as intended under normal operation. Tests include the operation of fans and motors, damper modulation, filter seals, sensor accuracy, thermostat and BMS functionality, and correct sequencing of ventilation units.

4. Performance Qualification (PQ)

This is the most intensive phase of validation, focusing on environmental performance. PQ verifies that the system delivers the required airflow rates, pressure differentials, temperature, humidity, cleanliness levels, and noise performance. Examples include testing for air changes per hour, room pressurisation (positive or negative), filter integrity (e.g. DOP/PAO testing), particulate counts (as per ISO 14644), microbial sampling, and airflow direction via smoke testing.

Key Tests Involved:

• Airflow volume testing using anemometers or balometers
• Pressure differential measurement using manometers
• Air changes per hour calculation based on room volume and measured airflow
• HEPA filter leak testing with DOP/PAO aerosol challenge
• Particle count testing for ISO cleanroom classification
• Temperature and humidity checks using calibrated loggers
• Noise level measurement (especially in open plan offices or clean zones)
• Smoke testing for airflow direction and leakage detection

Applicable Regulations and Standards in the UK

HVAC validation must conform to several regulatory documents, depending on the facility type:

• HTM 03-01 for healthcare ventilation validation
• HTM 04-01 for healthcare water and air systems
• ISO 14644-1 for cleanroom classification
• BS EN 12599 for airflow and performance testing
• EU GMP Annex 1 for pharmaceutical cleanrooms
• CIBSE Guide B and TM13 for commercial HVAC design and hygiene
• Building Regulations Part F (ventilation) and Part L (energy performance)

Deliverables from HVAC Validation

The outcome of HVAC validation is a structured report that includes the following:

• Summary of test results and compliance status
• System descriptions and performance ratings
• Test procedures and raw data
• Calibration certificates for test equipment
• Photographic evidence of testing where applicable
• Recommendations for remedial action if non-conformances are found
• A formal validation certificate signed by a competent engineer or commissioning specialist

Frequency of Validation

Full HVAC validation is performed upon installation or major system modification. In healthcare and pharmaceutical settings, revalidation is typically required annually or following changes to layout, occupancy, or equipment. HEPA filters are usually tested every 12 months. Revalidation may also be needed in response to audit findings or post-incident investigations.

Why HVAC Validation Matters

HVAC validation ensures that environmental controls are properly implemented to safeguard occupant health, meet legal obligations, and protect product or process integrity. It also supports energy performance goals, accreditation schemes (such as BREEAM or WELL), and long-term asset management by identifying system inefficiencies or installation defects early.

Why is Seasonal Commissioning Important?

Building systems such as heating, cooling, ventilation, and controls perform differently depending on external temperatures and internal loads. Some settings or faults only become evident when the building is exposed to:

• Cold winter conditions (e.g. underperforming boilers or frozen pipework)
• Hot summer conditions (e.g. inadequate cooling or overheating in offices)
• Variable occupancy patterns (e.g. holiday periods, staff fluctuations)

Seasonal commissioning ensures:

• Year-round occupant comfort
• Energy-efficient operation
• Fine-tuning of Building Management Systems (BMS)
• Correction of seasonal imbalances or design oversights
• Compliance with energy-related requirements (e.g. Part L, BREEAM credits)

When Does Seasonal Commissioning Occur?

Seasonal commissioning typically occurs:

• At least once in the winter and once in the summer
• 4 to 12 months after building handover
• As part of a soft landings approach or extended commissioning programme

It may be scheduled as a single visit during each seasonal period, or through continuous monitoring over time.

Systems Included in Seasonal Commissioning

1. Heating Systems

• Boilers, heat pumps, underfloor heating
• Radiators and control valves
• Frost protection settings
• Occupancy and time control response in colder months

2. Cooling Systems

• Chillers, VRF/VRV systems
• Fan coil units (FCUs), chilled beams
• Thermostat and BMS summer setpoints
• Performance under full load in warm weather

3. Ventilation and Air Handling Units (AHUs)

• Heat recovery units and bypass controls
• Air volume and temperature regulation during both extremes
• Condensation control and humidification

4. Building Management System (BMS)

• Sensor calibration for temperature, CO₂, humidity
• Seasonal setpoint adjustments and night setback strategies
• Optimisation of control sequences based on live data

5. Domestic Hot and Cold Water

• Water temperature stability
• Legionella control measures under different seasonal demands

6. Renewable Systems

• Solar thermal performance in summer
• Air source heat pumps during low external temperatures

Key Activities During Seasonal Commissioning

• Review and analyse energy consumption data across seasons
• Conduct site inspections and interviews with occupants and facilities staff
• Test and confirm seasonal BMS logic, time schedules, and override functions
• Verify the operation of weather compensation, frost protection, and free cooling
• Check for comfort complaints, noise issues, or air quality concerns linked to season
• Implement fine-tuning of valves, setpoints, fan speeds, and damper positions
• Produce a seasonal commissioning report with findings, adjustments, and recommendations

Regulatory and Best Practice Guidance (UK)

• CIBSE Commissioning Code M – emphasises seasonal commissioning as part of the commissioning strategy
• CIBSE TM39 – supports seasonal performance analysis through metering
• CIBSE Soft Landings Framework – encourages ongoing support post-occupancy, including seasonal testing
• Building Regulations Part L – seasonal efficiency is a key requirement of energy performance compliance
• BREEAM – seasonal commissioning is required to achieve credits under the ‘Man 01’ section (Management)

Typical Deliverables

• A seasonal commissioning plan (developed early in the project or during commissioning)
• Detailed logs of tests and measurements across both summer and winter
• Adjustments made to controls and mechanical systems

A Seasonal Commissioning Report summarising:

• System performance
• Comfort issues resolved
• Energy savings achieved
• Outstanding issues and recommendations

Benefits of Seasonal Commissioning

• Optimises building systems for comfort and efficiency all year
• Identifies performance issues that are not evident during initial commissioning
• Reduces long-term energy consumption and costs
• Supports occupant satisfaction and retention
• Helps achieve and maintain compliance with regulations and certifications (e.g. BREEAM)
• Minimises reactive maintenance by proactively addressing faults

What Are Water Treatment Services?

Water treatment in commercial offices refers to a range of professional services designed to manage the quality and safety of water used within the building’s systems. This includes domestic (potable) water, closed-loop HVAC water, and wastewater systems. The goal is to ensure water is safe for use, prevent equipment damage, and minimise health risks, such as Legionella.

Types of Water Systems in Commercial Offices

1    Domestic Water Systems

    ◦    Hot and cold water supply to kitchens, WCs, showers, and drinking outlets

    ◦    Risk of microbial growth, especially Legionella and Pseudomonas

2    Closed Circuit Heating and Cooling Systems

    ◦    Chilled water systems (CHW), low temperature hot water (LTHW), or condenser water loops

    ◦    Susceptible to corrosion, scaling, and sludge formation

 

3    Water Storage Systems

    ◦    Cold water storage tanks

    ◦    Calorifiers (hot water storage) or water heater 

4    Drainage and Wastewater

    ◦    Wastewater systems may be treated for odour or microbial build-up (especially in large or semi-occupied buildings)

Key Objectives of Water Treatment

    •    Control of microbial growth (e.g. Legionella, bacteria)

    •    Prevention of scale, corrosion, and biofilm formation

    •    Compliance with legal and regulatory standards

    •    Protection and longevity of mechanical assets

    •    Assurance of drinking water quality

    •    Reduction of energy consumption and water wastage

Core Water Treatment Services Provided

1    Legionella Risk Assessment

    ◦    Required under the Health & Safety at Work Act and ACoP L8

    ◦    Identifies risks in the water system that may promote Legionella growth

    ◦    Conducted every 2 years, or after changes to the system or occupancy

    

2    Water Testing and Sampling

    ◦    Routine microbiological analysis (Legionella, coliforms, E. coli)

    ◦    Chemical testing (pH, conductivity, hardness, TDS, chlorine levels)

    ◦    Carried out by UKAS-accredited laboratories

    

3    Water System Disinfection

    ◦    Thermal disinfection (raising temperatures to kill bacteria)

    ◦    Chemical disinfection (e.g. chlorine dioxide, silver-stabilised hydrogen peroxide)

    ◦    Used for new systems, post-maintenance, or after contamination

    

4    Closed System Water Treatment

    ◦    Addition of corrosion inhibitors, biocides, and scale preventers

    ◦    Monitoring of dissolved oxygen, iron levels, and microbial counts

    ◦    Advised under BSRIA BG29 and BG50 for pre-commissioning and ongoing treatment

    

5    Tank Cleaning and Inspection

    ◦    Annual inspection and physical cleaning of cold water storage tanks

    ◦    Ensures tanks are structurally sound, free from sediment, corrosion, and microbial contamination

   

 6    Water Softening and Filtration

    ◦    Used where water hardness is high to prevent scale build-up

    ◦    Softening units, filters, and UV disinfection may be installed depending on local supply conditions

    

7    Monitoring and Reporting

    ◦    Regular checks of sentinel outlets for temperature control

    ◦    Digital logbooks or paper-based records for audit and compliance

    ◦    Ongoing system monitoring through Building Management Systems (BMS) where integrated

Legal and Regulatory Requirements in the UK

    •    Health and Safety at Work Act 1974

    •    Control of Substances Hazardous to Health (COSHH) 2002

    •    Approved Code of Practice L8 (ACoP L8)

    •    HSG274 Part 2 – Legionella guidance for hot and cold water systems

    •    BS 8558 – Design and operation of water supply systems

    •    BSRIA BG29 and BG50 – Guidance on water treatment in building systems

    •    Water Supply (Water Fittings) Regulations 1999

Maintenance and Monitoring Schedule

    •    Monthly: Temperature checks at sentinel points

    •    Quarterly: Shower head and outlet cleaning; biocide dosing checks

    •    Annually: Tank inspection and clean, system disinfection if required

    •    Every 2 years: Legionella risk assessment

    •    As required: Water quality sampling and corrective treatment

Benefits of Water Treatment in Commercial Buildings

    •    Ensures occupant safety and well-being

    •    Prevents Legionnaires’ disease and waterborne illnesses

    •    Protects HVAC and plumbing infrastructure

    •    Reduces maintenance costs due to corrosion and scaling

    •    Maintains regulatory compliance and audit readiness

    •    Improves energy efficiency by maintaining optimal heat transfer conditions

Common Documentation and Deliverables

    •    Legionella risk assessment reports

    •    Water sampling certificates from UKAS labs

    •    Disinfection records and logbooks

    •    Closed-loop system test results and treatment records

    •    Asset register for tanks, calorifiers, and outlets

    •    Schematic diagrams of the water systems

What is Commissioning Management?

Commissioning Management is the coordinated process of planning, overseeing, and verifying that building systems — especially mechanical, electrical, public health (MEP), and specialist systems — are designed, installed, tested, and operated in accordance with the owner’s project requirements (OPR) and design intent.

Unlike direct commissioning, which focuses on individual system performance, commissioning management ensures that the entire commissioning process is organised and integrated across the project lifecycle — from design and construction to handover and post-occupancy.

Commissioning Managers act on behalf of the client, main contractor, or project team to manage risk, quality, compliance, and programme delivery related to building services.

Purpose and Value of Commissioning Management

    •    Ensures systems operate efficiently and reliably from day one

    •    Avoids costly rework, delays, and disputes during handover

    •    Improves energy performance and user comfort

    •    Helps meet BREEAM, LEED, WELL, and Soft Landings requirements

    •    Provides documented evidence of compliance with UK regulations

Scope of Commissioning Management

Commissioning Management typically applies to the following systems:

    •    Mechanical systems (HVAC, ventilation, pumps, chillers, boilers)

    •    Electrical systems (lighting, power, generators, UPS, switchgear)

    •    Public health systems (water, drainage, gas)

    •    Specialist systems (fire alarms, smoke control, BMS, AV, security)

    •    Low carbon and renewable technologies (heat pumps, PV, energy recovery)

    •    ICT, structured cabling, and building connectivity

Key Responsibilities of the Commissioning Manager

1    Developing the Commissioning Strategy

        ◦    Define commissioning scope, goals, and milestones

        ◦    Establish a commissioning plan based on project timelines and build sequence

        ◦    Coordinate input from the client, design team, main contractor, and    ssubcontractor’s

   

2    Reviewing Design and Technical Submissions

        ◦    Evaluate design specifications for commissioning feasibility

       ◦    Review control strategies, equipment selections, and performance data

       ◦    Identify commissioning-critical path issues early in the process

    

3    Creating and Managing the Commissioning Programme

        ◦    Integrate commissioning activities into the main construction programme

        ◦    Sequence testing and inspections logically (e.g., water flushing before pressure testing)

        ◦    Track progress and align with Practical Completion (PC) and Handover dates

    

4    Overseeing Pre-Commissioning Activities

        ◦    Witness factory acceptance testing (FAT) and site acceptance testing (SAT)

        ◦    Ensure installation sign-offs, QA checks, and system readiness

        ◦    Manage pre-cleaning of ductwork and pipework (BSRIA BG29 and BG49 compliance)

    

5    Coordinating System Commissioning

        ◦    Supervise functional testing, balancing, and calibration

        ◦    Coordinate input from all subcontractors and specialist suppliers

        ◦    Ensure test equipment is calibrated and staff are competent

    

6    Managing Documentation and Handover

        ◦    Compile test results, commissioning sheets, and inspection reports

        ◦    Review Operation and Maintenance (O&M) manuals and as-fitted drawings

        ◦    Ensure BMS graphics, user training, and seasonal commissioning plans are complete

    

7    Post-Occupancy Support

        ◦    Manage seasonal commissioning (summer and winter checks)

        ◦    Monitor system performance after occupancy (soft landings approach)

        ◦    Address fine-tuning and defect resolution

Industry Standards and Best Practices

    •    CIBSE Commissioning Code M – Management-level guidance for all commissioning stages

    •    CIBSE Code A, B, C, D – Specific codes for HVAC, water, and controls commissioning

    •    BSRIA BG 6 – Design framework for building services

    •    BSRIA BG 8, BG 33, BG 29, BG 50 – Guidance on documentation, air and water systems, and ongoing treatment

    •    BREEAM Man 01 and Hea 02 – Require commissioning management plans and IAQ verification

    •    Building Regulations – Part L (energy efficiency), Part F (ventilation), and TM44 inspections

Commissioning Management Plan Contents

A typical commissioning management plan includes:

    •    Project overview and stakeholder roles

    •    Commissioning objectives and strategy

    •    System matrix (which systems require commissioning and who is responsible)

    •    Programme milestones and sequencing

    •    Testing procedures and methods

    •    Witnessing and verification protocols

    •    Documentation standards

    •    Handover and post-occupancy support plan

Benefits of Effective Commissioning Management

    •    Achieves smoother project handover and fewer post-completion issues

    •    Ensures systems meet performance expectations and statutory requirements

    •    Enhances building quality, safety, and long-term maintainability

    •    Supports sustainability targets and certification schemes

    •    Provides transparency, accountability, and confidence for all parties

Role of the Commissioning Manager vs. Commissioning Engineer

The Commissioning Manager is focused on planning, coordination, and project-level risk management. They oversee the entire commissioning process across all trades.

The Commissioning Engineer performs the hands-on functional testing, balancing, and system fine-tuning for specific systems such as HVAC, electrical distribution, or BMS.

Both roles work closely together, but the Commissioning Manager ensures everything happens in the correct sequence, to the required standard, and on schedule.