G4/VM1: Ventilation verification method

G4 VENTILATION VERIFICATION METHOD G4/VM1 General and Ventilation rate and air purity Part 1. General 1.1 Introduction 1.1.1 Scope of this document 1.1.1.1 This verification method can be used for commissioning ducted mechanical systems and verification of air purity in workplaces achieved by ventilation. 1.1.2 Items outside the scope of this document 1.1.2.1 There are no specific items outside the scope of this document. 1.1.3 Compliance pathway 1.1.3.1 This verification method is one option that provides a means of establishing compliance with the functional requirements and performance criteria in Building Code clause G4 Ventilation. 1.1.3.2 If this verification method cannot be followed in full, use an alternative means to demonstrate compliance. Part 2. Ventilation rate and air purity 2.1 Ventilation rate 2.1.1 Verification of the design 2.1.1.1 In ducted mechanical ventilation systems, the air-flow rate (and consequently number of air changes), may be verified using the methods of measurement given in the CIBSE Code Series A, Appendix A3.1. 2.1.1.2 For determining the volume of outdoor air, measurements shall be taken close to the outdoor air inlet. 2.2 Air purity 2.2.1 Verification of the design 2.2.1.1 The acceptability of indoor air purity for workplaces may be verified by demonstrating that contaminant levels do not exceed the limits recommended in the Worksafe document “Workplace Exposure Standards and Biological Exposure Indices”. MINISTRY OF BUSINESS, INNOVATION AND EMPLOYMENT 28 JULY 2025 Page 5