8.1 Fixed building services must be commissioned to ensure that they use no more fuel and power than is reasonable in the circumstances. On-site electricity generation systems must be commissioned to ensure that they produce as much electricity as is reasonable in the circumstances. The commissioning process should involve testing and adjusting the fixed building services and on-site electricity generation as necessary and in accordance with the manufacturer’s instructions.
8.2 Fixed building services should be commissioned with the aim of optimising their in-use performance, with reference to Section 5 and Section 6 of this approved document, which provide further guidance on minimum efficiencies, controls and other relevant standards.
8.3 For large or complex projects, a commissioning manager should be appointed. In all other cases, the appointment of a commissioning manager should be considered on a case-by-case basis. The competence of the commissioning manager should meet the list of knowledge and skills set out in CIBSE’s Commissioning Code M.
8.4 When installing a fixed building service, or on-site electricity generation that is subject to the energy efficiency requirements, a commissioning plan should be prepared that identifies all of the following.
a. The systems to test.
b. The tests to complete.
c. Schedule of commissioning.
d. Roles and responsibilities.
e. Documentation requirements.
The building control body should be given all of the following.
a. The commissioning plan.
b. The design-stage target primary energy rate and building primary energy rate calculation.
c. The design-stage target emission rate and building emission rate calculation.
The building control body can then check that commissioning is being done as the work proceeds.
8.5 If the only controls for a fixed building service or on-site electricity generation are ‘on’ and ‘off’ switches, this particular service does not need to be commissioned.
8.6 Any commissioning should be carried out in accordance with all of the following procedures.
a. CIBSE’s Commissioning Code M.
b. Any of the following.
i. The specific CIBSE Commissioning Codes relevant to each service being commissioned.
ii. The specific BSRIA Commissioning Guides relevant to each service being commissioned.
iii. A combination of (i) and (ii).
c. The procedures for air leakage testing of ductwork given in paragraphs 8.10 to 8.13.
Notice of completion
8.7 A commissioning notice must be given to the relevant building control body and the building owner confirming that commissioning has been carried out for the installed fixed building services and on-site electricity generation according to the procedures in this section. The notice should confirm all of the following.
a. That the commissioning plan has been followed.
b. That all systems have been inspected in an appropriate sequence and to a reasonable standard.
c. That test results confirm that the performance of the system is reasonably in accordance with the actual building design, including written commentary on any areas where building services do not perform as well as intended.
8.8 The notice of completion of commissioning should be given as follows.
a. If a building notice or full plans have been given to a local authority building control body, the notice should be given within five days of the commissioning work being completed.
b. If the building control body is an approved inspector, the notice should generally be given to the approved inspector within five days of the work being completed.
c. In other cases – for example, if the work is carried out by a person registered with a competent person scheme – the notice must be given to the building control body within 30 days of the work being completed.
8.9 Where fixed building services and on-site electricity generation that require commissioning are installed by a person registered with a competent person scheme, that person may give the notice of completion of commissioning.
Air leakage testing of ductwork
8.10 For ducted systems that are served by fans with a design flow rate greater than 1m3/s, ductwork leakage tests should be carried out. Tests should follow the procedures in the Building and Engineering Services Association (BESA) documents DW/143 and DW/144.
8.11 For low-pressure ductwork, if at least 10% of the ductwork is tested at random and achieves the low-pressure standard as defined by DW/143, a calculated improvement in both the building primary energy rate and building emission rate may be claimed. Details are given in the National Calculation Methodology Modelling Guide.
8.12 Membership of the BESA Specialist Ductwork Group or the Association of Ductwork Contractors and Allied Services (ADCAS) is one way of demonstrating suitable competency for ductwork pressure testing work.
8.13 Air leakage rates are given in Table 8.1. If a ductwork system fails to meet the air leakage limit in Table 8.1, both of the following apply.
a. Remedial work should be carried out to achieve satisfactory performance in retests.
b. Further ductwork sections should be tested as set out in DW/143.
Table 8.1 Ductwork pressure classes
