CIOB 06 December 2011 Managing Contaminated Land Gavin Allsopp - - PowerPoint PPT Presentation

CIOB 06 December 2011 ‘Managing Contaminated Land’

Gavin Allsopp – Senior Environmental Engineer

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

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

Who are NHBC?

NHBC’s Purpose

 Raising standards in the new house building industry  Provide consumer protection for new home buyers

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”

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.”

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

• f the land in question is an appropriate person”

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

• riginal polluter

Legislation & Policy

Part 2A – underlying principles

 Suitable for Use  Polluter Pays principle  Cost Benefit  Reasonableness

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.

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.

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

Legislation & Policy

Planning Part 2A

 Addresses all sites  Identifies Statutory

‘Contaminated Land’

 Current Use where

there are unacceptable risks

 Addresses those

subject to redevelopment only

 Ensures land is not

determined as ‘Contaminated Land’

 Considers proposed

future use

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

But…….

Part 2A and PPS23 Under Review……

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.

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’

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.

Some examples are:

Human Health

Contaminant Effects Arsenic Carcinogenic Cadmium Kidneys and Bones, Lung Cancer Lead Intellectual Development BaP Carcinogenic Hydrocarbons Irritant, difficulty in breathing, impacts on blood, liver, kidneys, lungs……

Pollutant Linkages

 Contaminant – Pathway – Receptor

Source Pathway Receptor No linkage = no risk under Part 2A

Key Concepts

Key Concepts

Conceptual Site Model

 Textural or graphical

representation of the relationships between source(s), pathway(s) and receptor(s)

NHBC Buildmark Warranty

 Valid Claims -  Financial limits -

Contaminated Land Cover included under section 5 of warranty

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

• f:

 £1 million for a newly built Home; or  £500,000 for a converted Home

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.

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

NHBC Chapter 4.1 – The Basics

NHBC Standards Chapter 4.1

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

NHBC Processes and Procedures.

Initial Assessment (Desk Study)

 Review documentary evidence Historical Maps Public registers Geology Hydrogeology Geotechnical Hazards

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!

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!

!

NHBC Processes and Procedures.

Storage Tanks? Odours? Cracks in buildings? Staining/colouring? Fly tipping? Asbestos? Heating facilities? What’s over the boundary?

NHBC Chapter 4.1 – The Basics Where Hazards are suspected



Detailed Investigation - Required to determine extent

• f Geotechnical and

Contamination hazards



Specialist Involvement - Required to manage hazards

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’

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)

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)

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

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 !

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

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

NHBC validation procedures

‘Clean’ capping?

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

NHBC Risk Management

Three Mechanisms

 Notification through registration process  NHBC’s ‘in-house’ check  Feedback from Building Inspectors  Specialists

NHBC Risk Management

 Declare hazards at the time of registration using SNIN

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

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

NHBC Risk Management

Chartered Environmentalists Chartered Geologists Chartered Scientists Chartered Waste Manager Specialist in Land Condition

NHBC has a range of contaminated land specialists

Ex Consultants Ex Contaminated Land Officers Ex Environment Agency

NHBC - The Finalling Process

 Previously known as the CML initiative

• Problem with occupation of unfinished properties
• Revised Finalling Process implemented April 2003

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

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

Thank You for Listening Questions?