An overview of the changes to the Scottish Technical Handbooks 2007

by John Boanson
Architect/ Technical authoring coordinator

Introduction

On 1 May 2007, the revised Scottish Technical Handbooks came into force. Not all Handbooks underwent revision. Those were affected were:

• Introduction and Section 0 – General
• Section 1 – Structure
• Section 4 – Safety (and consequential changes to Section 3)
• Section 6 – Energy (and consequential changes to Section 3).

The latest revisions align the Handbooks closer to the England and Wales Approved Documents and the Energy Performance of Building Directive (EPBD). Section 2 is currently being revised to amend means of escape and allow fire engineering solutions.

In addition to the above amendments, mention should also be made to the Historic Scotland Guide which was published in mid-March and has the same status as the Technical Handbooks. It contains workable solutions to traditional buildings for use in conversion work.

The Procedural Handbook was republished with minor amendments, information on the EPBD, and contains a pull-out example of an energy certificate.

Technical Handbook changes

Section 0 – General

With regard to exempted buildings (Schedule 1), flats and maisonettes are now treated the same as houses.

Minor changes have been made to ‘Work not requiring a warrant’ (Schedule 3) with improved guidance for type 1, 2, 5-7 & 19 buildings.

Other changes include minor amendments to Schedule 6 and a new regulation has been added to cover continuing requirements for air-conditioning systems.

Section 1 – Structure

Changes have been made to:

• Standard 1.1 – Structure
• Standard 1.2 – Disproportionate collapse
• Domestic/ Non-domestic variations
• Small buildings structural guidance.

Standard 1.1 has been amended to take into account the effect on the stability of another, adjacent building. This includes both the imposition of increased loads on an adjacent building supporting strata and the lowering of the grounds water table, by for example, the construction of a basement.

Standard 1.2 introduces disproportionate collapse into the design of structures in a similar manner to the guidance in Approved Document A for England and Wales. The guidance to Standard 1.2 covers all buildings and is authored on a risk based methodology. The process of deciding what measures need to be taken is relatively straightforward:

1. Determine the building’s risk group based on the consequence classes in the Eurocode.
2. Assess the additional measures based on the risk group.
3. Design the additional measures. These may be the provision of horizontal ties, vertical and horizontal ties or, in fact no additional measures may need to be taken.

The Small Buildings Guide which was last revised in June 1994 has had its Standards updated, has new guidance added and is now accessible on the web. In scope, it applies to domestic buildings of up to 3 storey masonry construction and up to 2 storey timber frame construction. It contains additional geotechnical and foundation guidance, ground level differences, wall ties, new wind and snow loads, timber framed walls and updated timber span tables.

Section 4 – Safety [and consequential changes to Section 3 – Environment]

This section has been updated to take account of Disability Discrimination Act, BS 8300, PAN 78 and other publications of good practice. It addresses the needs of people with differing ability, not just disabled people and takes into account changing needs of the users.

Section 4 – Non-domestic remains largely unchanged, however 4.8(e) now applies to ventilation and electrical controls.

Section 3 – Non-domestic has been amended in respect of sanitary facilities, which include accessible facilities. There are no longer separate, reduced, standards for ambulant disabled facilities.

Section 3 – Domestic has been amended to ensure that facilities are provided on the principal living level, or that the principal living area can accommodate future facilities, to accommodate the needs of the occupants as they change over the years.

Section 4 – Domestic now has guidance covering, e.g. space for prams on the main entrance level, future provision of stairlifts, door entry systems, increased minimum door widths, tactile paving to external steps, and guidance on location of ventilation and electrical controls.

Section 6 – Energy [and consequential changes to Section 3 – Environment]

Changes have been made to the functional standards. As with E&W, SAP 2005 (Domestic)/ SBEM (Non-domestic) are to be used to calculate satisfactory emission rates and the elemental method is to be used when calculating U-values for conversions, alterations and extensions. Basically the methodology for calculating emissions is:

• Calculate the emissions for a notional building of the same size, shape, orientation etc. as the proposed dwelling (target)
• Calculate the emissions for the proposed dwelling
• Compare emissions for the notional and proposed dwellings
• Compliance is achieved if the proposed is equal or less than the target.

Energy performance certificates (EPCs) will be required at completion of construction, sale and rental. EPCs remain valid for 10 years and must be attached to the building. The domestic certificate has ratings for environmental impact and energy efficiency, whereas the non-domestic certificate is based solely on energy performance. The certificates can be produced through the SAP & SBEM software packages. Timescale for EPC introduction:

• Construction - May 2007
• Sale - Summer 2008
• Rental - Jan. 2009
• Public buildings - Jan. 2009.

Unlike E&W, there is no statutory requirement for air testing, however if testing is not carried out then the SBEM software uses a default leakage rate of 15 m³/m/hr.

Consequential revisions to Section 3 include amended guidance to include:

• Heating within insulation envelope
• Conditions to cover vulnerable people
• Buildings with low air infiltration rate
• Ventilation systems
• Biomass fuels.

 
Related NBS information:

Articles:

• 2008 changes to the Scottish Technical Handbooks

Selected links:

• Official and governmental information, UK

Written July 2007

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