8/12/2019 B.M1.10-M&E Design Criteria-Solar Gains and Shading

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Strategic Planning and Standards Group: email sp&s@cornwall.gov.uk.

Ref: B.M1.10 - Mechanical and Electrical Design Criteria

Title: Solar gains and shading

Rev: 0

Date: October 2012

Solar gains and shading generally

The application of solar shading can reduce solar gain in summer reducingair-conditioning costs and allows solar heat gain in winter, thereby savingheating costs. Solar shading is generally achieved with internal/external

blinds or tinted glazing.

This section documents the standards that must be complied with (via

Building Regulations and Health & Safety Executive) and refer to some

sources of advice and guidance. Meeting these national standards issufficient.

Legislation, regulations and advice documents

Various regulations, codes, standards and guidance on solar gains andshading are applicable and these include the following:-

The Building Regulations, A p p r o v e d d o c u m e n t s L 2 , Conservation offuel and power

CIBSE TM 3 7 Design for improved solar shading control

BSRIA,Rules of Thumb ( B G 9 / 2 0 1 1 ) - Guidelines for building

services (5th Edition) BRE R ep o r t 3 6 4 ,Solar shading of buildings

CIBSE Gu i d e F , Energy efficiency in buildings

Building Research Establishment TrustR e p o r t FB 9 Summertime

solar performance of windows with shading devices

Building Research Establishment, Information Paper I P 1 0 / 9 5 .Daylighting design for display-screen equipment(1995)

T h e H e a l t h a n d S af e t y ( D i sp l a y Sc r e e n Eq u i pm e n t )

R eg u l a t i o n s 1 9 9 2

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Ref: B.M1.9 - Mechanical and Electrical Design Criteria

Title: Solar gains and shading

Rev: 0

Date: October 2012

(continued from page 1)

For schools,Only one of the following parameters can be exceeded:

There should be no more than 120 hours when the temperature inthe classroom rises above 28C

The average internal to external temperature difference should notexceed 5C (i.e. the internal temperature should be no more than

5C above the external temperature on average)

The internal temperature during occupied hours should not exceed

32C.

In buildings other than schoolsReasonable provision would be to:

Limit solar and internal casual gains to 35 W/m or

Demonstrate that internal temperatures do not exceed 28C for morethan a reasonable number of hours (e.g. 20 hrs/annum for offices).

External blinds generally are more efficient than internal blinds for reducingsolar gains.

Horizontal shading devices are most effective at reducing peak summersolar gain, but large overhangs can reduce the availability of daylight.

Overhangs are most effective above south, southeast or southwest facingwindows.

In spaces where good day-lighting is required but which could be prone to

overheating, high performance glass with a high visible transmittance andlow g value (total solar transmittance) should be considered.

Where computers etc are used, windows shall be fitted with a suitable

system of adjustable covering to attenuate the daylight falling on theworkstation. Usually this will usually mean adjustable blinds the occupantcan control. Such blinds may be required in addition to special glazing or

external shading for control of solar gain. Blinds should be opaque/closewoven with a visible transmittance less than 0.1.

Strategic Planning and Standards Group: email sp&s@cornwall.gov.uk.