BS EN 12237:2003 – Ventilation for buildings — Ductwork — Strength and leakage of circular sheet metal ducts
1 Scope
This European Standard specifies requirements and test methods for strength and air leakage of circular ductwork used in air conditioning and ventilation systems in buildings.
The standard is intended to establish the mechanical strength and leakage required to verify the fitness for the intended service as installed ductwork.
The standard is intended for testing specific installations as well as product series in general under in-situ or laboratory conditions. The requirements and methods are applicable also to rectangular ductwork in respect of air leakage.
A recommended procedure, if the permitted air leakage rate is exceeded when testing a specific installation, is given in informative annex A.
2 Normative references
This European Standard incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text, and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments).
CR 12792:1997, Ventilation for buildings – Symbols and terminology.
prEN 14239:2001, Ventilation for buildings – Ductwork – Measurement of ductwork surface area.
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this European Standard the terms and definitions given in CR 12792:1997 apply.
3.1.1
duct surface area A j
surface area of the ductwork under test
[see prEN 14239:2001]
3.1.2
total joint length L
actual total length of the periphery of the installation joints included in the test section of the ductwork
3.1.3
test pressure p test
static air pressure difference between the pressure within the ductwork to be tested and the pressure of the surrounding air
3.1.4
design operating pressure p design
maximum static air pressure difference at which the installed ductwork is designed to operate under normal conditions
3.1.5
static pressure limit p s
maximum design operating pressure for the ductwork according to its air tightness class
NOTE The static pressure limits, positive and negative, for the appropriate air tighness class are specified in Table 2.
3.1.6
air leakage rate q v
air leakage flow rate of the ductwork under test
3.1.7
measured air leakage rate q vlmeasured
air leakage flow rate before correction
3.1.8
air temperature t
temperature of the air during the test
3.1.9
atmospheric pressure p a
barometric pressure of ambient air during the test
3.1.10
air leakage factor f
leakage flow rate per unit surface area of the duct (f = q v I A j )
3.1.11
air leakage limit f max
maximum permitted leakage factor for the ductwork according to its air tightness class
BS EN 12237:2003 – Ventilation for buildings — Ductwork — Strength and leakage of circular sheet metal ducts