CIOB 06 December 2011 Managing Contaminated Land. Gavin Allsopp Senior Environmental Engineer

Transcription

1 CIOB 06 December 2011 Managing Contaminated Land Gavin Allsopp Senior Environmental Engineer

2 Contents: NHBC Legislation and Policy Human health effects Why is it an issue? NHBC Warranty and Chapter 4.1 managing ground conditions NHBC Verification Requirements NHBC Risk Management The Finalling Process - Council of Mortgage Lenders Initiative

3 Who are NHBC? The National House-Building Council - established 1936 Non-profit distributing company Unique stakeholder company structure 10 year Warranty introduced in 1968 Approved Inspector licence granted in 1985 (England and Wales) Insurance Company regulated by the FSA

4 Who are NHBC? NHBC s Purpose Raising standards in the new house building industry Provide consumer protection for new home buyers

5 Legislation & Policy Part 2A of the Environmental Protection Act 1990 Introduced in 01 April 2000 Provides a risk-based approach to the identification and remediation of land where contamination poses an unacceptable risk to human health or the environment. Provides legal powers to Local Authorities Have a Duty to inspect their area from time to time

6 Legislation & Policy Part 2A of the Environmental Protection Act 1990 Provides a definition of Contaminated Land Any land which appears to the local authority in whose area it is situated, to be in such a condition, by reason of substances in, on or under the land, that: (a) Significant harm is being caused or there is a significant possibility of such harm being caused; or (b) Pollution of controlled waters is being, or is likely to be, caused.

7 Legislation & Policy Part 2A Appropriate Person Class A - Any person who caused or knowingly permitted the substances, or any of the substances, by reason of which the contaminated land in question is such land to be in, on or under that land Class B - If no person has, after reasonable enquiry, been found who is an appropriate person to bear responsibility the owner or occupier for the time being of the land in question is an appropriate person

8 Legislation & Policy Part 2A Appropriate Person A developer/ builder may be classed as an appropriate person if they introduced the receptor to the site that created a significant pollutant linkage, irrespective of the original polluter

9 Legislation & Policy Part 2A underlying principles Suitable for Use Polluter Pays principle Cost Benefit Reasonableness

10 Legislation & Policy Planning (redevelopment) Bringing brownfield land into beneficial use. Suitable for use approach. Onus is on the developer to assess suitability of land and to provide appropriate evidence.

11 Legislation & Policy Planning Conditions are attached to planning consents: No unacceptable risks No new pollutant linkages No unacceptable contamination remains Only applies to site under development.

12 Legislation & Policy Planning PPS23 Implementation through Local Planning Authority Usually, EHO/CLO deal with contaminated land issues Contaminated land is a material consideration EA is a consultee Test is to show land is safe that under the proposed land use, it will not be contaminated land as defined in Part 2A

13 Legislation & Policy Part 2A Addresses all sites Identifies Statutory Contaminated Land Current Use where there are unacceptable risks Planning Addresses those subject to redevelopment only Ensures land is not determined as Contaminated Land Considers proposed future use

14 Legislation & Policy Is land contaminated land (Part 2A)? Is land fit for intended purpose (Planning and Building Control)? Suitable for use - clean up targets? Same risk-based approach applies in each case

15 But. Part 2A and PPS23 Under Review

16 Approved Document C Site preparation and resistance to contaminants and moisture Part C: Amended in 2004 to reflect Part 2A Contamination must be considered Requires a risk assessment same as Part 2A and Planning All land associated with the building must be considered.

17 Approved Document C Site preparation and resistance to contaminants and moisture C1- Site preparation and resistance to contaminants Reasonable precautions shall be taken to avoid danger to health and safety caused by contaminants on or in the ground covered, or to be covered, by the building and any land associated with the building. Adequate sub-soil drainage shall be provided if it is needed to minimise the risk of the transport of water borne contaminants to the foundations of the building

18 Approved Document C Site preparation and resistance to contaminants and moisture Hazard identification: Conceptual Site Model Hazard assessment: Identifying Pollutant Linkage Risk estimation Detail SI Report - must contain sufficient information to confirm CSM Remediation and Verification Reports required.

19 Human Health Some examples are: Contaminant Arsenic Cadmium Lead BaP Hydrocarbons Effects Carcinogenic Kidneys and Bones, Lung Cancer Intellectual Development Carcinogenic Irritant, difficulty in breathing, impacts on blood, liver, kidneys, lungs

20 Key Concepts Pollutant Linkages Contaminant Pathway Receptor Source Pathway Receptor No linkage = no risk under Part 2A

21 Key Concepts Conceptual Site Model Textural or graphical representation of the relationships between source(s), pathway(s) and receptor(s)

22 NHBC Buildmark Warranty Contaminated Land Cover included under section 5 of warranty Valid Claims - Financial limits - If substance/s within the site curtilage result, or could reasonably be expected to result in a Statutory Notice being served. The maximum claim relating to a Home under Section 5 is the Original Purchase Price, up to a maximum of: 1 million for a newly built Home; or 500,000 for a converted Home

23 NHBC Warranty - Claims Asbestos found by Homeowner in their garden Investigated and found in 5 plots Investigation and Remediation cost Approx 500k. When they go wrong they can be costly to rectify.

24 NHBC Chapter 4.1 The Basics Basic Framework for managing geotechnical and contamination issues Sites assessed and investigated with a minimum of a desk study and Walkover Survey Any hazards = Site investigation Required. Sites are properly remediated and/or appropriate design precautions are taken Appropriate documentation and validation provided

25 NHBC Standards Chapter 4.1

26 NHBC Chapter 4.1 The Basics. An Initial Assessment is required on all sites to indicate any potential hazards at an early stage Desk study Site walkover Conceptual Site Model

27 NHBC Processes and Procedures. Initial Assessment (Desk Study) Review documentary evidence Historical Maps Public registers Geology Hydrogeology Geotechnical Hazards

28 NHBC Processes and Procedures. Search Companies Information can be provided from the likes of Landmark, GroundSure etc. BUT This alone does not constitute a DESK STUDY and it doesn t tell you everything about the site!

29 NHBC Processes and Procedures. Walkover Survey Reveals issues that were not otherwise apparent Builds a better understanding of the site Need to be aware of Health & Safety!!

30 NHBC Processes and Procedures. Storage Tanks? Asbestos? Odours? Cracks in buildings? Staining/colouring? Fly tipping? What s over the boundary? Heating facilities?

31 NHBC Chapter 4.1 The Basics Where Hazards are suspected Detailed Investigation - Required to determine extent of Geotechnical and Contamination hazards Specialist Involvement - Required to manage hazards

32 NHBC Chapter 4.1 The Basics. Where Hazards are Known Further investigation is required to fully assess risk Manage Hazard- Develop Remediation Strategy including Verfication

33 NHBC Verification Procedures Aim of remediation is to break pollutant linkages Source Reduction (excavation, bioremediation) Pathway Management (soil capping, gas/radon membranes) Receptor Protection/Modification (restrict land use change site layout)

34 NHBC Verification Procedures Construction phase remediation Gas/Radon/Hydrocarbon resistant membranes Soil capping to garden/landscaped areas (Usually designed as part of the Remediation Strategy by an engineer) (Method statement for how this will be validated should be included within the Remediation Strategy for approval by NHBC/LA prior to commencement of works)

35 NHBC Verification Procedures Soil capping: Usually up to 1m depth in gardens Usually 300mm depth for communal landscaping Should include minimum of 100mm topsoil (Ch 9.2) Remainder usually subsoil May also include a geotextile marker layer and capillary break layer at the base

36 NHBC Verification procedures Expectations Sampling frequency 1 per 3 to 1 per 5 gardens (dependent on site size) Sampling based on volumes acceptable, but should be agreed in advance If sampling is from source only then should be undertaken by an independent person (i.e. not supplier), be recent and from stockpile allocated for your site and suitably fenced off Sampling post importation should either be from stockpile at pre agreed sampling frequency or on sites with space restrictions from gardens post placement Sampling usually takes a minimum of 5 days at the laboratory therefore the earlier the samples are taken the better!

37 NHBC Verification Procedures Verification of soil capping Should be undertaken by a competent person (in accordance with NHBC Standards and Rules) Usually independent contractor or specialist sub contractor unless alternative agreed prior to commencement of works Competent in obtaining verification sampling data

38 NHBC Verification Procedures Reporting Objective to document all aspects of remediation Descriptive site, remediation objectives, remediation techniques, verification and monitoring data in text Including supporting drawings, figures, maps, photographs etc

39 NHBC validation procedures Clean capping?

40 NHBC validation procedures Common Pitfalls - Summary Insufficient number of samples/verification trial pits Samples from supplier older than 6 months old Range of contaminants insufficient Source of topsoil unknown Waste transfer notes/topsoil delivery tickets not submitted Verification report unclear

41 NHBC Risk Management Three Mechanisms Notification through registration process NHBC s in-house check Feedback from Building Inspectors Specialists

42 NHBC Risk Management Declare hazards at the time of registration using SNIN

43 NHBC Risk Management In House Checks - Landmark Report NHBC in-house check A Landmark Report will not identify all Hazards and should not be considered a Desk study

44 NHBC Risk Management Site Inspections Eyes & Ears of NHBC NHBC Building Inspectors Site Survey prior or minimum at commencement Key stage inspections - foundations, load bearing walls, roof, pre hand-over & drainage Engineering notes are copied to inspectors

45 NHBC Risk Management NHBC has a range of contaminated land specialists Ex Consultants Ex Contaminated Land Officers Ex Environment Agency Chartered Environmentalists Chartered Geologists Chartered Scientists Chartered Waste Manager Specialist in Land Condition

46 NHBC - The Finalling Process Previously known as the CML initiative Problem with occupation of unfinished properties Revised Finalling Process implemented April 2003

47 NHBC - The Finalling Process NHBC set Red and/or Builder Responsible conditions Warranty to be in place before legal completion Red conditions will prevent finalling and the sale Red conditions: No Buildmark = No = No Sale

48 NHBC - The Finalling Process Red Conditions Initial Assessment Site Investigation Gas Risk Assessment Gas Protection Measures Remediation Strategy Verification Report required Verification of depth of capping Green Conditions Copies of Regulatory Correspondence

49 Thank You for Listening Questions?