AS 1668.2-1991

1 - AS 1668.2-1991 THE USE OF MECHANICAL VENTILATION AND AIR-CONDITIONING IN BUILDINGS - MECHANICAL VENTILATION .....
4 - PREFACE
5 - CONTENTS
7 - SECTION 1 SCOPE AND GENERAL
7 - 1.1 SCOPE
7 - 1.2 APPLICATION
7 - 1.2.1 Mechanical systems
7 - 1.2.2 Natural systems of carparks
7 - 1.3 REFERENCED DOCUMENTS
9 - 1.4 DEFINITIONS
9 - 1.4.1 Airflow rate (herein referred to as ‘flow rate’)
9 - 1.4.2 Air-handling plant
9 - 1.4.3 Air-handling system
9 - 1.4.4 Air lock
9 - 1.4.5 Air outlet
9 - 1.4.6 Approved and approval
9 - 1.4.7 Duct
9 - 1.4.8 Enclosure
9 - 1.4.9 Exhaust air
9 - 1.4.10 Exhaust-air intake
9 - 1.4.11 Exhaust outlet
9 - 1.4.12 Exposure standard (ES)
9 - 1.4.13 General exhaust ventilation
9 - 1.4.14 Grease filter
9 - 1.4.15 Hood
9 - 1.4.16 Incinerette
9 - 1.4.17 Indoor air
9 - 1.4.18 Infiltration air
9 - 1.4.19 Leakage air
9 - 1.4.20 Local exhaust
10 - 1.4.21 Make-up air
10 - 1.4.22 May
10 - 1.4.23 Objectional effluents
10 - 1.4.24 Occupied zone
10 - 1.4.25 Outdoor air
10 - 1.4.26 Outdoor air intake
10 - 1.4.27 Plant room
10 - 1.4.28 Plenum
10 - 1.4.29 Privacy lock
10 - 1.4.30 Recycle air
10 - 1.4.31 Regulatory Authority
10 - 1.4.32 Relief air
10 - 1.4.33 Required
10 - 1.4.34 Return air
10 - 1.4.35 Shall
10 - 1.4.36 Should
10 - 1.4.37 Spill air
10 - 1.4.38 Supply air
12 - SECTION 2 SUPPLY AIR DILUTION PROCEDURE
12 - 2.1 SCOPE OF SECTION
12 - 2.2 OUTDOOR-AIR INTAKES
12 - 2.2.1 Location
12 - 2.2.2 Passage of air
12 - 2.3 OUTDOOR AIRFLOW RATES
12 - 2.3.1 General
12 - 2.3.2 Occupancy
12 - 2.3.3 Minimum outdoor airflow rates, (qf ), to be supplied to an enclosure, based on area of the enclosure
14 - 2.3.4 Minimum outdoor airflow rates, (qf ), to be supplied to an enclosure, based on number of occupants in the enclosure
14 - 2.3.5 Minimum flow rate of outdoor air into a single-enclosure system (qF )
14 - 2.3.6 Minimum flow rate of outdoor air into a system serving a group of enclosures (QF )
15 - 2.3.7 Variable air volume systems
15 - 2.3.8 Make-up air requirement
15 - 2.4 PROHIBITION OF RECYCLE AIR
16 - 2.5 OUTDOOR AIR MIXING AND DISTRIBUTION
16 - 2.6 OUTDOOR AIR FLOW
16 - 2.6.1 Systems serving enclosures in which the temperature may exceed 27°C under normal operation
16 - 2.6.2 Systems serving enclosures with transient or variable occupancy
19 - SECTION 3 EXHAUST AIR DILUTION PROCEDURE
19 - 3.1 SCOPE OF SECTION
19 - 3.2 GENERAL EXHAUST VENTILATION
19 - 3.2.1 General
19 - 3.2.2 Exhaust locations
19 - 3.2.3 Enclosures served by both supply and general exhaust systems
19 - 3.3 LOCAL EXHAUST
19 - 3.3.1 Types of effluents requiring local exhaust
19 - 3.3.2 Effluent removal
19 - 3.3.2.1 General requirements
19 - 3.3.2.2 Type A effluents removal
19 - 3.3.2.3 Type B effluents removal
20 - 3.4 AIR FROM ENCLOSURES HAVING EXHAUST-AIR REQUIREMENTS
20 - 3.4.1 General requirements
20 - 3.4.2 Return-air intake location
20 - 3.4.3 Air pressures
20 - 3.5 REPLENISHMENT OF EXHAUST AIR
20 - 3.5.1 Source
20 - 3.5.2 Amount
20 - 3.5.3 Pressure drop
20 - 3.5.4 Electrical interlocking of exhaust and make-up
20 - 3.6 COMBINATION OF EXHAUST SYSTEMS
20 - 3.7 AIR DISCHARGES
20 - 3.7.1 General
21 - 3.7.2 Discharges not deemed objectionable
21 - 3.7.3 Obnoxious discharges
21 - 3.7.4 Disposal of rainwater and condensate
22 - SECTION 4 VENTILATION OF ENCLOSURES USED BY VEHICLES WITH INTERNAL COMBUSTION ENGINES
22 - 4.1 SCOPE OF SECTION
22 - 4.2 APPLICATION OF SECTION
22 - 4.3 GENERAL CASE
22 - 4.4 CARPARKS
22 - 4.4.1 General
28 - 4.4.2 Airflow rates
29 - 4.4.3 Air openings
30 - 4.5 ENCLOSURES OTHER THAN CARPARKS
30 - 4.5.1 Enclosed driveways associated with buildings
30 - 4.5.2 Loading docks
30 - 4.5.3 Automotive service and repair shops
30 - 4.5.4 Vehicular lifts and shafts
30 - 4.5.5 Areas used by special-purpose vehicles
31 - 4.6 QUEUING AREAS
31 - 4.6.1 General
31 - 4.6.2 Queuing length
31 - 4.6.3 Airflow rate and distribution of air
32 - 4.7 AIR PRESSURE
32 - 4.8 REPLENISHMENT OF EXHAUST AIR
32 - 4.9 EXHAUST-AIR DISCHARGE
32 - 4.10 STAFF-VENTILATION RATE
32 - 4.11 LOCATION OF EXHAUSTS IN BELOWGROUND ENCLOSURES
32 - 4.12 ENERGY SAVING
32 - 4.13 MONITORING OF ATMOSPHERIC CONTAMINANTS
32 - 4.13.1 General
32 - 4.13.2 System requirements
33 - 4.13.3 Operation and accuracy of AC monitors
33 - 4.13.4 Analysis of AC and operation of mechanical ventilation
34 - 4.13.5 Sampling points
34 - 4.13.6 Monitor failure
34 - 4.13.7 Marking, commissioning, reliability and records
35 - APPENDIX A - MINIMUM OUTDOOR-AIR REQUIREMENTS BASED ON CLASS OF OCCUPANCY
39 - APPENDIX B - MINIMUM EXHAUST AIR REQUIREMENTS BASED ON USE OF ENCLOSURE
40 - APPENDIX C - OUTDOOR AIR CONTAMINANT LEVELS
41 - APPENDIX D - DERIVATION OF THE MULTIPLE ENCLOSURE FACTOR AND EQUATIONS FOR FILTRATION EFFICIENCIES .....
41 - D1 DERIVATION OF THE MULTIPLE ENCLOSURE FACTOR*
44 - D2 REQUIREMENTS FOR AIR CLEANING EFFICIENCY WITH SOME AIR CLEANING ARRANGEMENTS
44 - D2.1 Symbols
44 - D2.2 Single Enclosure
44 - D2.2.1 Air treatment for particulates
45 - D2.2.2 Air treatment for particulates and odours
45 - D2.3 Multiple enclosure systems
45 - D2.3.1 Central air cleaning unit serving all enclosures
46 - D2.3.2 Air cleaning units for each enclosure
47 - D2.3.3 Air cleaners on the supply to each enclosure
48 - D2.3.4 Air cleaners for the critical enclosure only
50 - D2.3.5 Combination of a central air-cleaning unit and a recirculating air-cleaning unit for the critical enclosure
64 - APPENDIX E - KITCHEN EXHAUST HOODS
64 - E1 SCOPE
64 - E2 APPLICATION
64 - E3 HOOD DESIGN AND MANUFACTURE
64 - E3.1 General
64 - E3.2 Manufacture
64 - E3.3 Openings
64 - E3.4 Internal lights
64 - E4 DISTANCE FROM GREASE ARRESTING DEVICE TO HEAT SOURCE
64 - E4.1 General
64 - E4.2 Reduction of distances
65 - E5 DISTANCE TO FLOOR LEVEL
65 - E6 OPERATION INDICATOR
65 - E7 KITCHEN EXHAUST HOODS INCORPORATING GREASE FILTERS
65 - E7.1 Grease filters
65 - E7.2 Grease arresting filters
65 - E7.3 Hood gutters
65 - E7.4 INTERNAL SURFACE
65 - E7.4.1 Sloping
65 - E7.4.2 Profile
65 - E7.5 Distance from grease gutter to perimeter of appliance
65 - E8 KITCHEN EXHAUST HOODS INCORPORATING GREASE REMOVAL DEVICES
66 - APPENDIX F - CAPTURE OF EMISSIONS BY KITCHEN EXHAUST HOODS
66 - F1 GENERAL
66 - F2 FACTORS INFLUENCING EXHAUST FLOW RATE
66 - F3 CALCULATION OF EXHAUST AIRFLOW RATE
69 - F4 CAPTURE VELOCITY
70 - APPENDIX G - A PERFORMANCE APPROACH TO ACCEPTABLE INDOOR AIR QUALITY
70 - G1 SCOPE
70 - G2 PROPOSAL SUBMISSION
70 - G3 DESIGN OBJECTIVES
70 - G4 INDOOR AIR QUALITY PROCEDURE
70 - G4.1 General
70 - G4.2 Quantitative evaluation
71 - G4.3 Subjective evaluation
71 - G4.4 Monitoring
71 - G4.5 Information to be provided
72 - APPENDIX H - VENTILATION REQUIREMENTS FOR INCINERETTES
73 - APPENDIX J - RATIONALE FOR LAG OR LEAD TIME FOR TRANSIENT OCCUPANCY
74 - APPENDIX K - BASIS FOR LENGTH OF VEHICLE QUEUE
74 - K1 CARPARKS WITH PAY BOOTHS
74 - K2 CARPARKS WITHOUT PAY BOOTHS
75 - APPENDIX L - EXAMPLES OF LAYOUTS OF CARPARK VENTILATION
80 - APPENDIX M - AUTOMATIC MONITORING SYSTEMS FOR CARPARKS MARKING, COMMISSIONING, RELIABILITY AND RECORDS
80 - M1 MARKING
80 - M2 COMMISSIONING
80 - M3 RELIABILITY
80 - M4 RECORDS

Sets out the requirements for air handling systems which ventilate enclosures by mechanical means. It sets minimum requirements for preventing an excess accumulation of airborne contaminants, or objectionable odours. It does not prescribe other requirements associated with comfort such as temperature, humidity, air movement or noise. The Standard also includes requirements for natural ventilation at carparks. Road tunnels are not addressed in this Standard.

This Standard sets out requirements for air-handling systems which ventilate enclosures by mechanical means, where such systems are required by a Regulatory Authority. It sets minimum requirements for preventing an excess accumulation of airborne contaminants, or objectionable odours. These minima are based on needs for body odour control, food odour control, air contaminant control, or carbon dioxide concentrations or a combination of any or all of these factors, depending on the particular situation. It does not prescribe other requirements associated with comfort, such as temperature, humidity, air movement or noise. This Standard also includes requirements for natural ventilation of carparks. Road tunnels are outside the scope of this Standard.NOTES:1 Fire-safety aspects related to air-handling systems are covered in AS 1668.1.2 It is recommended that air-handling systems be designed, constructed and installed so that their use does not give rise to a nuisance arising from noise or vibration. For guidance on noise and vibration control see AS 1055 and AS 2107.

First published as AS 1668.2-1976.
Second edition 1980.
Third edition 1991.