Acoustics vs Overheating — What do the requirements of Approved Document O mean for new residential development?
This is a summary of an article that was originally published on our blog about acoustics, overheating and Approved Document O.
On 15 June 2022, Approved Document O (ADO) came into effect. This document presents the requirements of Part O of Schedule 1 of the building regulations, which aims to protect the health and welfare of occupants of new residential buildings by reducing the occurrence of high indoor temperatures. Contained in Approved Document O are two requirements relating to night-time noise levels. But how are these relevant to overheating? And what impact will they have on the thermal assessments and design of new residential premises going forward? Let’s find out.
Approved Document O (ADO) applies to new residential buildings. According to section 0.3, these are defined as:
· Residential (dwellings)
· Residential (institutional)
· Residential (other)
The requirement does not apply to hotel rooms.
Requirement O1 states,
“Requirement O1 Overheating mitigation
1) Reasonable provision must be made in respect of a dwelling, institution or any other building containing one or more rooms for residential purposes, other than a room in a hotel (“residences”) to-
a. Limit unwanted solar gains in summer;
b. Provide an adequate means to remove heat from the indoor environment.
2) In meeting the obligations in paragraph (1)-
a. Account must be taken of the safety of any occupant, and their reasonable enjoyment of the residence; and
b. Mechanical cooling may only be used where insufficient heat is capable of being removed from the indoor environment without it.
“In locations where external noise may be an issue … the overheating mitigation strategy should take account of the likelihood that windows will be closed during sleeping hours (11pm to 7am).
Windows are likely to be closed during sleeping hours if noise within bedrooms exceeds the following limits.
a. 40dB LAeq,T, averaged over 8 hours (between 11pm and 7am).
b. 55dB LAFmax, more than 10 times a night (between 11pm and 7am).”
So in effect, what this tells us is that building designers should not rely on openable windows to provide cooling, if the internal noise levels are going to exceed these thresholds as a result.
For reference, LAeq noise levels can be thought of as an average noise level over the course of the night, while LAFmax noise levels represent individual events (cars backfiring or sirens).
#architecture #design #development #cibse #overheating #noise #acoustics
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