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AS 4740:2025
$164.15
Natural ventilators – Classification and performance
AS 4740:2025 specifies requirements for ventilators designed to provide ventilation of enclosures by means of the natural flow of air.
Table of contents
Header
About this publication
Preface
1 Scope and general
1.1 Scope
1.2 Application
1.3 Normative references
1.4 Terms and definitions
1.5 Classification
1.5.1 Type classification
1.5.2 Performance classification
1.5.3 Dual classification
1.5.4 Corrosion resistance
2 Performance testing
2.1 Type approval
2.2 Type testing
2.2.1 General
2.2.2 Range type
2.2.3 Specimen size
2.2.4 Scale models
2.3 Performance requirements
2.3.1 Rain resistance
2.3.2 Effective aerodynamic area
2.3.3 Flow coefficient
2.3.4 Wind loading
2.3.4.1 Static load tests
2.3.4.2 Free field tests
2.4 Instrumentation
2.4.1 Airflow rate
2.4.1.1 Measurement
2.4.1.2 Calibration
2.4.2 Pressure
2.4.2.1 Measurement
2.4.2.2 Calibration
2.4.3 Temperature measurement
2.4.4 Water flow meters
2.4.5 Timers
2.4.6 Rain gauge
3 Performance calculations for natural ventilators
3.1 Scope
3.2 Stack pressure airflow
3.2.1 Stack pressure
3.2.2 Airflow
3.3 Wind siphoning airflow
3.3.1 Wind siphoning pressure
3.3.2 Airflow
3.4 Combined effect
3.5 Nominal performance
4 Information and marking
4.1 Product information
4.2 Marking
5 Test reports
5.1 General
5.2 Preliminary information
5.3 Test information
5.3.1 Rain leakage test
5.3.2 Discharge coefficient and effective aerodynamic area test
5.3.3 Flow coefficient test
5.3.4 Wind load resistance tests
5.4 Deviations from standard test procedure
Appendix A
A.1 General
A.2 Information to be supplied by the buyer
A.3 Published data
A.4 Specification example
Appendix B
B.1 Scope
B.2 Principle
B.3 Apparatus
B.4 Measurements
B.4.1 Water collection
B.4.2 Airflow rate measurement
B.4.3 Water eliminator performance test
B.4.3.1 General
B.4.3.2 Installation
B.4.3.3 Procedure
B.5 Test specimen and calibration plate
B.5.1 Test specimen
B.5.2 Calibration plate
B.6 Procedure
B.7 Test results
B.8 Ventilator rain penetration classification
Appendix C
C.1 Scope
C.2 Principle
C.3 Apparatus
C.4 Procedure
C.5 Test results
C.5.1 Determination of rain leakage wind velocity (vr)
C.5.2 Ventilator performance classification
Appendix D
D.1 Scope
D.2 Principle
D.3 Apparatus
D.4 Test specimen
D.5 Procedure
D.6 Calculations
D.6.1 Discharge coefficient
D.6.2 Effective aerodynamic area
Appendix E
E.1 Scope
E.2 Principle
E.3 Apparatus
E.4 Mounting of test specimen
E.5 Procedure
E.6 Calculation
E.7 Alternative procedure
Appendix F
F.1 Scope
F.2 Principle
F.3 Apparatus
F.4 Mounting of test specimen
F.4.1 Air pressure test
F.4.2 Static load test
F.5 Test loads
F.6 Procedure
F.7 Pass criteria
Appendix G
G.1 Scope
G.2 Principle
G.3 Apparatus
G.4 Mounting of test specimen
G.5 Test loads
G.6 Procedure
G.7 Pass criteria
Appendix H
H.1 Scope
H.2 Principle
H.3 Apparatus
H.4 Mounting of the test specimen
H.5 Test loads
H.6 Procedure
H.7 Pass criteria
Appendix I
I.1 Scope
I.2 Statistical sampling
I.3 Product certification
I.4 Supplier’s quality system
I.5 Other means of assessment
Bibliography
Cited references in this standard
Please select a variation to view its description.
| Published | 28/03/2025 |
|---|---|
| Pages | 40 |
Please select a variation to view its pdf.
