Standard Assessment Procedure 2005 – Appendix Q MVHR Installation Guide
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Introduction
This document is to be used in support of the SAP Appendix Q scheme which provides
tested performance values for MVHR products.
Note that all checklist items must be answered YES in order for the SAP Appendix Q
test figures to be used in ‘As built’ SAP calculations. If any checklist items are answered
NO then SAP default figures must be used. Systems must be designed by a
manufacturer designer and sized correctly to qualify for SAP Appendix Q figures.
SECTION 1:
INSTALLATION GUIDANCE
1. Ductwork Installation
Decision
Yes, No or
N/A
Have the ducts been installed with as little air resistance and
leakages as possible (flexible ducts should be avoided)?
Note: Refer to HVCA DW/143 document ‘A Practical Guide to Ductwork Leakage
Testing’ for detailed guidance on air tightness. Rigid plastic ducting is
recommended and flexible duct should only be used in very short lengths and
mainly just to connect the ductwork to the units/diffusers or to overcome particular
obstructions.
If flexible ducting has been used, has it been pulled taut to minimise
system resistance?
Has the number of duct bends been minimised to ensure adequate
air flow and least resistance? Bends should have a minimum radius
at least the same as the diameter of the ducting used?
Refer to Figure 1 if using flexible ducting
Have the fans and ducting placed in unheated voids been insulated
to reduce the possibility of condensation forming (see notes below)?
Note: Ducts should be insulated with the equivalent of at least 25mm of insulating
material with a thermal conductivity of 0.04W/mK. Where a duct rises vertically it
may be necessary to fit a condensation trap in order to prevent backflow of any
moisture in the product. Insulation should be applied to both warm and cold air
ducts. Cold air ducts should be wrapped additionally with a vapour barrier outside
the insulation. Ducts with cold air running in warm environments will condense on
the outside of the duct.
Have recommended duct jointing collars and components been
used to ensure appropriate duct performance (duct runs should be
as air tight as possible)?
Note: All the joints should be sealed correctly either using duct tape or silicon.
