As1668 2

Notification of any inaccuracy or ambiguity found in an Australian Standard should be made without delay in order that the matter may be investigated and appropriate action taken. When occupancy is intermittent, infiltration may provide sufficient natural ventilation Emergency provisions may be needed Special case Special case continued.

For oven applications, the cooking surface area is deemed to be equivalent to the oven door area. In some cases, the area per occupant is greater than existing regulation for determination of exits and similar since ventilation needs are based on a time integrated requirement. Local exhaust airflow rates shall be in accordance with the relevant Australian Standards. The prevention of the malfunction of fire control equipment due to dust build-up reducing the ability of a system to respond to a fire event. This therefore places constraints on the wording of the Standard that would not otherwise be necessary.

Ventilation (Architecture)

The area of an equivalent aerodynamically perfect orifice, and equals the penetration area required by the natural ventilation device multiplied by the discharge coefficient determined under test. Reissued incorporating Amendment No. For the purpose of this Clause groups of enclosures used for a similar purpose and subject to the same density of occupancy such as general office space may be regarded as a single enclosure.

Australian Standard AS 1668.2-1991

Accessed by TAFE NSW - SYDNEY INSTITUTE - ULTIMO on 04 Oct 2007The use of mechanical ventilation

Guidance on the use of empirical calculations and computer modelling is given in the Supplement to this Standard. This will allow building regulations to reference a single Standard for virtually all aspects of the ventilation of buildings.

Methods of test Electrical equipment for explosive ventilationType of protection atmospheresProtection by. The need for the segregation of systems serving operating rooms should be assessed on a case by case basis. Permission may be conditional on an appropriate royalty payment.

This solution satisfies the Standard but may not be economical since all enclosures with lower ratios are oversupplied with outdoor air. Set points will vary depending on the occupancy of the car park i. This requirement does not preclude the use of additional filters in other parts of the airhandling system.

Building Code

The remainder of this document is available for purchase online at infostore. When the monitored condition is below the determined maximum concentration, the mechanical exhaust system may be stopped. The values of net floor area per occupant are approximate and conservative.

Australian Standard AS

Enclosures containing sanitary fixtures. As Windows in Buildings - Selection and Installation. Minimum ventilation rates specified may not ensure that specific contaminants e. Maintaining positive pressure at adjacent enclosures can be accomplished by the provision of a pressurized disconnecting compartment. In general, the values are in excess of the requirement needed to ensure healthy breathing or maintain acceptable levels of oxygen, carbon dioxide and the like.

Also a period of pre-purging may be required before entry of occupants to clear accumulation of pollutants generated by furnishings, other materials, and the like, within the space. Charcoal barbecue is required to have a separate exhaust system and hood. Suggestions for improvements to Australian Standards, addressed to the head office of Standards Australia, are welcomed. It may also be unacceptable to combine process exhausts or exhausts from laboratory fume cupboards during system operation.

Special case Special case Special case Special case Special case. The length of the hood shall not be less than the length of the kitchen appliance. The procedures provide for consideration of the effects of central and local recycle air cleaning, transfer air from other enclosures and exhaust air from particular enclosures if applicable. Statements expressed in mandatory terms in notes to Tables are deemed to be requirements of this Standard.

Mechanical exhaust with natural make-up. Manifold pressure generally, atmospheric pressure minus engine vacuum is depressed below atmospheric pressure by aspiration air path pressure losses. The airflow rates shall be such as will ensure positive capture and removal of the effluent.

Where there is reasonably predictable pollutant generation information and an authoritative community health exposure limit, then that information is used to set ventilation rates. The sections on kitchen exhaust and car park ventilation have been revised in line with the general performance philosophy. Requirements for specific occupancies located within these enclosures are also given. The reduction of energy consumption through the reduction of dirt build-up on heat transfer equipment.

Make-up air from an enclosure ventilated by a required exhaust system may be acceptable for unoccupied enclosures, for example, make-up air from a car park for a garbage room exhaust system. They shall also be positioned to minimize the entry of objectionable or noxious discharges. Natural supply with natural relief exhaust.

This Section applies to the mechanical ventilation requirements of particular types of health care enclosures, which differ from those of other mechanically ventilated enclosures. Substitution for the contaminant. However, the dynamics of these systems rely on very small pressure differentials caused by wind and air density, which makes the effect difficult and complex to predict. Three grades of ventilation amenity are provided with recommended dilution indices.

Type B effluents are more of a nuisance than dangerous, and the most common application would relate to kitchen exhaust hoods. Building owners and managers, fire insurance underwriters and other bodies may have requirements in excess of those required by this Standard. This Standard includes requirements for the ventilation of car parks. Where a combination of methods are used, the area of openings shall be determined on a proportional basis. This Standard does not prescribe other requirements associated with comfort, such as temperature, humidity, minnalae songs air movement or noise.

For low sidewall hoods, grease may be drained into removable collection containers. Information on ventilation effectiveness is given in the Supplement to this Standard. The alternative procedure should only be applied to cases where two or more cooking appliances are grouped together under one exhaust hood. Ventilation systems may be combined to meet the requirements of this Standard.

The amount of ventilation needed depends on the type and quantity of vehicles using the enclosures, the time for which vehicles engines operate, and the time that occupants spend in the enclosure. Ventilation rates are calculated on the following exposure criteria available at the time of publication. Enclosures containing unflued gas appliances. Continuous jointing and sealing with an appropriate compound unaffected by grease, water or cleaning agents that are in compression at the joint. At time of publication, Standards Australia was not aware of suitable test specifications for the determination of this efficiency.

Australian Standards are kept under continuous review after publication and are updated regularly to take account of changing technology. Air from a naturally ventilated portion shall not be used as make-up for the mechanically exhausted portion. In smoking prohibited occupancies, minimum ventilation rates are generally lower than those given in the edition of the Standard. Air filters are now a mandatory requirement for most air-handling systems.

Make-up air from an enclosure served by a non-required exhaust system in conjunction with a mechanical supply or natural ventilation system is not prohibited. Standards may also be withdrawn. If side skirts are used, the length of the exposed sides perimeter and, therefore, the air quantity may be reduced.

Accessed by TAFE NSW - SYDNEY INSTITUTE - ULTIMO on 04 Oct 2007