|
|
|
|
THIS APPENDIX IS NOT PART OF THE TECHNICAL STANDARDS OR THE DEEMED TO SATISFY PROVISIONS AND IS THEREFORE NON-MANDATORY. IT GIVES OUTLINE GUIDANCE ON THE PREPARATION OF A SITE WHERE HARMFUL OR DANGEROUS SUBSTANCES ARE SUSPECTED OR IDENTIFIED AND ON FLOOD DAMAGE TO BUILDINGS AND RADON PROTECTION MEASURES FOR NEW DWELLINGS.
Preparation of a site
1. Harmful or dangerous substances includes deposits of faecal or animal matter and any substance or mixture of substances which is, or could become, corrosive, explosive, flammable, radioactive or toxic or which produces, or could produce, any gas likely to have any such characteristic.
2. Where records or local knowledge of previous use identifies land which may contain, or give rise to, harmful or dangerous substances, planning permission will normally be subject to conditions. These conditions will be imposed to ensure that the development proposed for the land will not expose future users or occupiers, or any building or services, to hazards associated with the contaminants. Examples of land likely to contain contaminants are given in Table 1.
3. There may be occasions when land containing harmful or dangerous substances has not been identified at the planning stage, and the presence of contaminants is only suspected later. Some signs of the possible presence of contaminants are given in Table 2.
4. If any signs of possible contaminants are present the Local Authority should be told at once. If the presence of any of the contaminants listed in Table 2 is confirmed, it is likely that some form of remedial action will be required. For guidance, the normal course of remedial action is listed against each contaminant noted in Table 2. In all cases these courses of action assume that the ground to be covered by the building will have at least 100mm of in-situ concrete cover. Expert advice may be required to provide an economical and safe solution to the hazards encountered, especially where contaminants are present in large amounts or where there is imminent danger to health or safety.
5. With the increasing re-development of former industrial land in the UK, attention is also drawn to the British Standards Institution publication, first issued in April 1988 as a Draft for Development, DD 175: 1988 (1992), "Code of practice for the identification of potentially contaminated land and its investigation". This is designed to provide guidance on the identification and investigation of land where contaminants may exist and where hazards from undesirable substances may occur.
6. The subject is still relatively new and continues to develop, hence publication of DD 175 as a Draft for Development which is intended to complement both BS5930: 1981, "Code of practice for site investigations" and the guidance notes issued by the Department of the Environment’s Inter-Departmental Committee on the redevelopment of Contaminated Land.
Flooding
7. Serious river and coastal flooding which has occurred in a number of areas in Scotland is, unfortunately, not entirely preventable. Pressure for land development may mean that development proposals could be given planning approval on land subject to some risk of flooding. Paragraph 8 below refers to sources of information on measures to reduce the effects of flood damage to buildings.
8. Where development is to take place on land assessed by the planning authority as having a flood risk, advice should be sought from sources such as the local planning authority, the Scottish Environmental Protection Agency (SEPA) and those responsible for coastal defences. Further information is in "National Planning Policy Guideline 7: "Planning and Flooding", 1995". Detailed guidance on the likely effects of flooding on building materials and fabric and on the precautionary measures that can be taken in the design of dwellings to reduce the effects of flood damage can be obtained from "Design Guidance on Flood Damage to Dwellings, 1996". Both publications are available from the Stationery Office.
Radon
9. Radon is a naturally occurring, radioactive, colourless and odourless gas that is formed where uranium and radium are present. It can move through cracks and fissures in the subsoil, and so into buildings. Where this gas occurs under buildings, the external walls contain it and the containment of radon can build up inside the buildings over the long term posing a risk to health and increasing the risk of developing cancer.
The precise areas where measures will require to be taken to reduce radon penetration into dwellings are regularly reviewed by the Scottish Executive in light of advice from the National Radiological Protection Board. These are listed the the Building Research Establishment’s document "Radon: guidance on protection measures for new dwellings in Scotland".
Table 1 to Part G Appendix: Examples of land likely to contain contaminants
|
Examples of land likely to contain contaminants is land on which there has been - |
|
asbestos works; |
|
chemical works; |
|
gas works, coal carbonisation plants and ancillary by-products works; |
|
industries making or using wood preservatives; |
|
landfill and other waste disposal sites; |
|
metal mines, smelters, foundries, steel works and metal finishing works; |
|
munitions production and testing sites; |
|
nuclear installations; |
|
oil storage and distribution sites; |
|
paper and printing works; |
|
railway land, especially the larger sidings and depots; |
|
scrap yards; |
|
sewage works, sewage farms and sludge disposal sites; and |
|
tanneries |
Table 2 to Part G Appendix: Possible contaminants and actions
|
Signs of possible contamination |
Possible contaminant |
Probable remedial action required |
|
a. Vegetation (absence, poor or unnatural growth) |
metals, metal compounds |
none |
|
organic compounds, gases |
removal |
|
|
b. Surface materials (unusual colours and contours may indicate) |
metals, metal compounds |
none |
|
oil and tarry wastes |
removal, filling or sealing |
|
|
asbestos (loose) |
removal, filling or sealing [Note 1] |
|
|
other fibres |
none |
|
|
organic compounds including phenols |
removal or filling |
|
|
potentially combustible material including coal and coke dust |
removal or inert filling |
|
|
refuse and waste |
removal |
|
|
c. Fumes and odours (may indicate organic chemicals at very low concentrations) |
flammable, explosive, toxic and asphyxiating gases including methane and carbon dioxide |
removal |
|
the construction is to be free from unventilated voids |
||
|
corrosive liquids |
removal, filling or sealing [Note 1] |
|
|
faecal, animal and vegetable matter (biologically active) |
removal or filling |
|
|
d. Drums and containers (whether full or empty) |
various |
removal with all contaminated ground [Note 1] |
Note:
1. The local authority may require the removal to be done by specialists.
2. In the table -
REMOVAL means that the contaminant itself and any contaminated ground to be covered by the building should be taken out to a depth of 1m (or less if the Local Authority agrees) below the level of the lowest floor and taken away to a place to be named by the Local Authority;
FILLING means that the ground to be covered by the building is to be covered to a depth of 1m (or less if the Local Authority agrees) with a material which will not react adversely with any contaminant remaining and will be suitable for making up levels. The type of filling and the design of the ground floor should be considered together;
INERT FILLING means that the filling is wholly non-combustible and not easily changed by chemical reactions; and
SEALING means that a suitable imperforate barrier is laid between the contaminant and the building and sealed at the joints, around the edges and at the service entries. Note that polyethyl-ene may not be suitable if the contaminant is a liquid such as a tarry waste or organic solvent.
|
|
|