Yesterdays air pressure test was successful!
The figures achieved were 2.7 & 2.9 for No 68 & 70 respectively, which means that the contractor has just met the targets but not by much, so effort has not been wasted.
This means that no remedial work will be necessary, which is great because this would be very time consuming, costly and have an impact on programme and also a second test, as planned, will not be required.
Big congratulations to Nick on site who was probably biting his nails yesterday before the result.
Sadly I missed the test which only took about 45mins. and involved closing all openings, vents and ducts etc. and attaching a blower over an external door. The fan pressurises the building to 50 Pa and then calculates what volume of air is required to maintain this pressure so that the leakage rate can be calculated.
We required a minimum of 3 m3 (h.m2) for No 70 to ensure that the
MVHR (Mechanical Ventilation Heat Recovery) will function, and 4m3
(h.m2) for No 68 to satisfy heat loss requirements for Building
Regulations although both buildings were standardised at 3m3 (h.m2) by
the contractor to simplify the target.
(By comparison current building regulations require 10m3 (h.m3) and passivhaus 0.6)
The measurement is the volume of air in cubic metres that is lost through every square metre of the building fabric over an hour averaged through the whole building.
