[AOV question regarding degrees vent must open]

Thanks Tom, really appreciated

[AOV question regarding degrees vent must open]

Hi All

We manage a block that has two stairwells with one AOV in each stairwell. The maintenance company have since told me the openings do not conform (this is some 5 years after installation, it has passed every service) as they do not open to 140 degrees; and they want to replace the whole system at a cost of ~3k per vent

Having spoken to some other companies there does seem to be disagreement about whether this sort of opening is required (they open to about 60 degrees, 1m x 1m vent)

Does anyone have any input please?

Thanks in advance