M25 DBFO LUS Section 2

Transcription

1 M25 DBFO LUS Section 2 Final Use Assessment Noise Insulation Regulations Assessment JOB NUMBER: DOCUMENT REF: ATK-0809-S2-DOC-X For construction LAG AL NW SM July 2014 Originated Checked Reviewed Authorised Date Revision Purpose Description

2 Contents Section Page 1. Introduction 4 2. Regulations and Guidance Provisions of the Noise Insulation Regulations Statutory Traffic Noise Insulation Discretionary Traffic Noise Insulation Insulation of Buildings against Construction Noise Eligibility with Regard to the Noise Insulation Regulations Making Offers of Noise Insulation Noise Insulation Works to be Undertaken 6 3. Methodology Calculation of Road Traffic Noise, Results of Assessment 8 5. Summary 9 6. Conclusions 9 List of Figures Figure 4.1 Location 41 & 43 Chalkpit Lane 8 Figure 4.2 Detail for 41 & 43 Chalkpit Lane 8 2

3 Appendices Appendix A 10 A.1 Noise Insulation Regulations calculations 11 Appendix B 12 B.1 Lower Noise Surfacing Correspondence 13 3

4 1. Introduction This report details an assessment of the requirements under the Noise Insulation Regulations 1975 (as amended in 1988) for the M25 Widening for Section 2. A full environmental assessment of the scheme has been undertaken separately and is reported in the Stage 3 Environmental Assessment Report (EAR), reference ALL-DO-EN-216. This assessment has been undertaken based on the Atkins created NoiseMap SE model, produced for the EAR. 2. Regulations and Guidance 2.1 Provisions of the Noise Insulation Regulations The Noise Insulation Regulations 1975 (as amended 1988) set out the requirements under which buildings may qualify for both statutory and discretionary noise insulation. Additional guidance is given in Department of the Environment Circular 114/75. The Regulations include the following definitions: Relevant Noise Level The noise level expressed in db as LA10(18-Hour) one metre in front of the most exposed of any windows and doors in a facade of a building caused or expected to be caused by traffic using or expected to use any highway. Prevailing Noise Level The noise level expressed in db as LA10(18-Hour) one metre in front of the most exposed of any windows and doors in a facade of a building caused by traffic using any highway immediately before works for the construction of a highway or additional carriageway, or for the alteration of a highway, as the case may be, were begun. Relevant Date The date on which a highway or additional carriageway was first opened to public traffic, or in the case of an altered highway, the date on which it was first open to public traffic after the completion of the alteration. The Regulations also detail the criteria for qualifying windows and doors, which must be part of an eligible room. Note that the terms db (A) L10 (18-hour) and db LA10(18-Hour) have the same meaning. The provisions of the Regulations are summarised in the paragraphs below. 2.2 Statutory Traffic Noise Insulation Regulation 3 imposes a duty on the highway authority to offer insulation or provide grants in respect of a new road, or a road for which a new carriageway has been constructed, if the following four requirements are fulfilled: The Relevant Noise Level must be at least 68 db (A) L10 (18-hour). Note that calculated values of 67.5 db(a) are rounded up to 68 db(a). The Relevant Noise Level must be at least 1dB(A) more than the Prevailing Noise Level. New roads must contribute at least 1dB(A) to the Relevant Noise Level. The property must be within 300m of a carriageway forming part of the scheme. 4

5 The Noise Insulation Regulations require that noise levels are determined in accordance with the technical memorandum Calculation of Road Traffic Noise 1 (CRTN) Discretionary Traffic Noise Insulation There are two separate circumstances under which discretionary powers to provide noise insulation or grants are permitted. Under Regulation 4(1), the Highway Authority has discretionary powers to offer insulation if the four requirements listed in section 2.2 are fulfilled in respect of an altered road. Under Regulation 4(4), the highway authority has discretionary powers to insulate buildings which do not fulfil the above requirements but which form part of a contiguous facade with a qualifying building. 2.4 Insulation of Buildings against Construction Noise Paragraph 1 of Regulation 5 within the Noise Insulation Regulations states that Subject to and in accordance with the provisions of these Regulations, where works for the construction of a highway or additional carriageway or the alteration of a highway cause or are expected to cause noise at a level which, in the opinion of the appropriate highway authority, seriously affects or will seriously affect for a substantial period of time the enjoyment of an eligible building adjacent to the site on which the works are being or are to be carried out but in respect of which building no duty under Regulation 3 or power under Regulation 4(1) has arisen, the appropriate highway authority may carry out or make a grant in respect of the cost of carrying out insulation work in or to the building. 2.5 Eligibility with Regard to the Noise Insulation Regulations Some residential buildings are not eligible under the Regulations. To be considered as eligible, buildings must not be subject to compulsory purchase, closing, demolition or clearance orders, and houses must not be first occupied after the relevant date. Although mobile homes are also not eligible under the Noise Insulation Regulations, powers to provide grants in respect of mobile homes exist under the Highways Noise Payments and Moveable Homes (England) Regulations The Noise Insulation Regulations apply only to habitable rooms, and so exclude bathrooms, toilets, hallways, utility areas, and smaller kitchens that do not include living or dining areas. Rooms containing open-flued combustion appliances, gas cookers etc cannot be insulated without the presence of an uninsulated openable window in the room. Where the structure of the building is such that it cannot practicably be insulated, there are no duties to provide noise insulation. 1 Calculation of Road Traffic Noise (Department of Transport/Welsh Office 1988) 5

6 2.6 Making Offers of Noise Insulation The Noise Insulation Regulations require the highway authority to carry out a noise assessment in the terms described above and to publish a list or map identifying all buildings qualifying under Regulation 3, not later than six months after the relevant date, i.e. when the new road is first opened. Where necessary, they must immediately make offers of insulation to the occupier or landlord of the building, giving the person six months to accept. The highway authority is encouraged to make the offer prior to commencement of road construction so that residents may benefit during the construction period. However, some residents may prefer to wait until the road is opened before making a decision. Consequently, the offer is renewed for a further twelve months after opening. There is an appeals procedure whereby occupiers or landlords of buildings who claim to be affected by a new road may request the highway authority to make an offer. The highway authority must then review the noise calculations and either make an offer or set out their reasons for refusal. This procedure commences 6 months after the relevant date. 2.7 Noise Insulation Works to be Undertaken The insulation installation usually consists of an openable secondary window within the existing window, with an air gap of mm, depending on the thickness of the glass in the secondary window. Should the window face in a southerly direction, then a Venetian blind must be fitted in the air gap unless another form of sun shading is available. The room must be fitted with a noise attenuated mechanical ventilator unit to an approved specification unless adequate ventilation can be provided in an alternative manner. Where practicable, a second door should be installed behind each qualifying external door that opens into an eligible room. 3. Methodology 3.1 Calculation of Road Traffic Noise, 1988 The prevailing and relevant road traffic noise levels have been calculated at a sufficient number of representative receptors using the methodology detailed in the DoT technical memorandum Calculation of Road Traffic Noise (CRTN). CRTN is the methodology used to determine entitlement under the Noise Insulation Regulations 1975 (as amended 1988) (NIR) and is the accepted method for the prediction of traffic noise in the UK. The CRTN method of predicting noise from a road consists of five main stages: division of the road scheme into a number of segments; calculation of the Basic Noise Level, at a reference distance of 10m away from the nearside carriageway edge, for each road segment based on traffic data; for each segment, assessing the noise level at the reception point taking into account distance, ground attenuation and screening; 6

7 correction of the noise level at the reception point to take into account site layout features including reflections from buildings and facades, and the size of the source segments; a combination of the contributions from all segments within view is then taken to give the predicted noise levels at the reception point for all roads. This report provides results which include the effects of existing and future sections of reduced noise surfaces on the M25, in line with the current advice given in the DMRB (HD213/11, Revision 1) which is described in Appendix B The preferred method of assessment when implementing CRTN is to use prediction techniques. The prediction techniques may be implemented using appropriate computer software, such as NoiseMap SE, which was used for this assessment. NoiseMap SE undertakes calculations in strict accordance with CRTN. A noise model has previously been created by Atkins Acoustics using NoiseMap SE for the Section 2 EAR (Document Ref: ALL-DO-EN-216). The model used for The Noise Insulation Regulations assessment includes all scheme design elements, surfacing and traffic data described in that report, with the inclusion of additional bunding information at Clacket Lane as described within the technical note reported to Skanska Balfour Beatty in July The noise model has been updated with additional calculation points on facades of the buildings described in this report. 7

8 4. Results of Assessment Two properties have been identified as potentially qualifying for noise insulation. These properties are in the following location: 41 and 43 Chalkpit Lane, Oxted two properties. 41 and 43 Chalkpit Lane, Oxted These properties are located north of the M25 just on Chalkpit Lane, approximately 220 metres from the M25 and are shown in Figure 4.3. Figure 4.1 Location 41 & 43 Chalkpit Lane It was found that the east façade of the properties would meet the criteria to be considered as eligible under the discretionary powers of Regulation 4. The detail is shown in Figure 4.4, Figure 4.2 Detail for 41 & 43 Chalkpit Lane Inspection of online aerial photographs suggests that the east façades include windows and doors. 8

9 5. Summary On the basis of the data currently available, and taking into account the effects of reduced noise surfaces, the following façades containing potentially eligible windows or doors, are shown to qualify, as follows: Junctions 21A to 22 Chalkpit Lane 41 Chalkpit Lane, Oxted East façade 43 Chalkpit Lane, Oxted East façade These two properties, are subject to noise levels greater than 68dB(A), and are expected to be affected by a contribution of more than 1dB(A) from the altered carriageway and experience an increase of more than 1dB(A) relative to the prevailing situation. Therefore, these properties could be offered insulation under the discretionary powers of Regulation 4 of the Noise Insulation Regulations. It is noted that the increase in noise at these properties is primarily due to traffic changes on Chalkpit Lane, which is shown to rise from an 18hour AAWT flow from approximately 3600 in 2015 to a flow of approximately 4700 in The flow on this road in 2030 is expected to occur either with or without the scheme. Without knowledge of the use of the rooms that may require noise insulation and the exact interior layout of each of the properties it is not possible to conclude for certain whether or not there are eligible rooms behind these qualifying facades. 6. Conclusions Two properties are shown to qualify for noise insulation, and the increase in noise is primarily due to traffic changes on Chalkpit Lane, which is shown to rise from an 18hour AAWT flow from approximately 3600 in 2015 to a flow of approximately 4700 in The flow on this road in 2030 is expected to occur either with or without the scheme. 9

10 Appendix A Noise Insulation Regulations Criteria Calculations for Identified Selected Properties within 300m of Section 2 10

11 A.1 Noise Insulation Regulations calculations The table below identifies all properties that may qualify for noise insulation and selected adjacent properties that fall below the criteria to qualify. Lines shaded in orange meet the criteria for noise insulation. NoiseMap ID Address Floor Potential Count Façade Direction Prevailing Noise Level Relevant Noise Level Noise From Altered Roads Noise From All Other Roads 17 41, Chalkpit Lane 0 1 S Yes Yes No 17 41, Chalkpit Lane 1 1 S Yes Yes No & 43, Chalkpit Lane 0 2 W Yes No & 43, Chalkpit Lane 1 2 W Yes No & 43, Chalkpit Lane 0 2 E Yes Yes Yes Yes & 43, Chalkpit Lane 1 2 E Yes Yes No Chalkpit Lane 0 1 S Yes No Chalkpit Lane 1 1 S Yes Yes No & 47 Chalkpit Lane 0 2 W Yes No & 47 Chalkpit Lane 1 2 W Yes No & 47 Chalkpit Lane 0 2 E Yes Yes No & 47 Chalkpit Lane 1 2 E Yes Yes No Chalkpit Lane 0 1 S Yes Yes No Chalkpit Lane 1 1 S Yes No Chalkpit Lane 0 1 W Yes No Chalkpit Lane 1 1 W Yes No Chalkpit Lane 0 1 E Yes Yes No Chalkpit Lane 1 1 E Yes Yes No Relevant >68? Change >1? Contribution >1? Possible NIR Qualification? 11

12 Appendix B Lower Noise Surfacing Correspondence 12

13 B.1 Lower Noise Surfacing Correspondence CRTN 1988 provides procedures for predicting noise from hot rolled asphalt, concrete and pervious road surfaces. It states that for road surfaces and traffic conditions which do not conform to these requirements a separate correction to the basic noise level is required Although CRTN does not provide a correction for Thin Wearing Courses, a correction is provided in the DMRB, however the DMRB is not required to be followed for a Noise Insulation Regulations assessment. 13