MANX GAS LTD. Avoiding Danger from Underground Services

Transcription

1 MANX GAS LTD Avoiding Danger from Underground Services Information and Advice from Manx Gas Edition Date: November 2011 MGD001 Rev 2

2 Contents 1 Introduction Consequence of damage to plant can include: Manx Gas Ltd Service Provision Planning Works Your responsibilities Why does damage occur? What happens if I damage a pipe? Further Information Graphic Representations of Gas Mains Methods of Working Proximity of Other Plant Backfill Materials Damage to Coatings Hot Works Demolition Tree Planting Deep Excavations Building Proximities Site Responsibilities Manx Gas Contact Details Avoiding Danger from Underground Services - Summary... 8 Manx Gas Dialb4udig Procedure No. 3 - Rev 2 1

3 Avoiding Danger from Underground Services GENERAL CONDITIONS AND PROTECTIVE AND PRECAUTIONARY MEASURES TO BE OBSERVED FOR THE PROTECTION OF APPARATUS AND THE PREVENTION OF DISRUPTION TO GAS SUPPLIES 1 Introduction This information is aimed at The Department of Infrastructure, Local Authorities, Developers and other large scale organisations. Manx Gas Ltd owns, operates and maintains the gas distribution network throughout the Isle of Man with exception for the high pressure Natural Gas Pipeline that is operated by the MEA. The majority of this network consists of polyethylene and metallic buried pipes operating at pressure up to 75mbarg. The pressures in the network are controlled through Pressure Reduction Installations (PRIs) and a series of pressure sensors and recorders which are sited above ground. These general conditions apply only to the gas apparatus and pipes operated by Manx Gas Ltd. The high pressure natural gas line from Glen Moor to Pulrose and the Natural gas extension pipeline to pressure reduction stations outside Ramsey; Peel and Port St Mary is operated by the MEA any enquiries relating to these areas should be addressed to the MEA. 2 Consequence of damage to plant can include:- The consequences of damaging a Gas pipe can include:- Major fire/explosion leading to death and serious injury Asphyxiation due to gas exposure leading to death and serious injury Loss of supplies to individuals or communities Financial cost of reparation and remedial works Enforcement action by HSWI 3 Manx Gas Ltd Service Provision Free provision of plans; 28 days notice is required and plans are valid for 28 days. Free provision of site visits including marking; 7 working days notice is required. 4 Planning Works As part of the planning process, the party responsible for the works should send a copy of their proposals to Manx Gas Ltd by , post or fax (contact details page 6). Manx Gas Ltd will supply the current plans of the gas network in the vicinity of the works, together with general guidance within 28 days. This service is free, except where the request for information forms part of a legal search. In this case, a charge is made for each search. Where the work is in the vicinity of plant operating above Low Pressure (75mbar), Manx Gas dial before you dig service should be contacted to arrange a site survey. Notice of at least seven working days should be allowed. A representative from Manx Gas Ltd will then visit the site to mark out the plant and advise on safe working practices. Where the plant operates at below 75mbar (Low Pressure), the guidance in HS(G)47 should be followed. In particular, digging in the vicinity of known or suspected pipes should always be by hand. It Manx Gas Dialb4udig Procedure No. 3 - Rev 2 2

4 should also be noted that small diameter gas services operating at pressures below 75mbar are NOT indicated on Manx Gas Ltd plans. 5 Your responsibilities It is the responsibility of the party undertaking the works to ensure that they have complied with the relevant legislation and HSE guidance. Key legislation includes:- Construction (Design & Management) Regulation 2007 New Roads and Street Works Act (NRSWA) HS(G)47 Avoiding Danger from Underground Services Pipelines Safety Regulations (PSR) Health & Safety at Works Act Management of Health and Safety at Work 2003 The UK Health & Safety Executive document HSG47, Avoiding danger from underground services, is downloadable for free In practice, this means that those undertaking works should have hard copy plans preferably in colour available on site for reference both prior to and during any works activities. You must verify the details provided on plans by; tracing and hand digging then marking position on site with suitable markers. If a site survey is needed it is the responsibility of the party undertaking the works to request this at a suitable time, the paint to mark gas mains is biodegradable so has a limited life. Manx Gas advise parties to request marking of mains when needed within a reasonable time before work is to commence as remarking is not done unless special circumstances arise. 6 Why does damage occur? Investigation of damages to gas plant show a number of key factors were to blame, including:- Poor Planning Breakdown in communications Failure to seek advice and guidance from the plant owner (i.e., Manx Gas Ltd) Failure to utilise safe digging practices as described in HS(G)47 Avoiding Danger from Underground Services 7 What happens if I damage a pipe? All cases of damage, however minor, must be reported to Manx Gas Ltd Emergency number Manx Gas Ltd will attend site to inspect the damage and carry out repairs as required. All plant damage is investigated, and all third party damage is reported to the Isle of Man Health & Safety at Work Inspectorate (HSWI). Manx Gas Ltd will recover all reasonable costs incurred in attending to repairing damages to plant. If damage or leakage is caused or an escape of gas is smelt or suspected the following action should be taken at once: Remove all personnel from the immediate vicinity of the escape. Inform Manx Gas using the Gas Emergency Number on Manx Gas Dialb4udig Procedure No. 3 - Rev 2 3

5 Prevent any approach by the public, prohibit smoking, and extinguish all naked flames or other sources of ignition for at least 15 metres from the leakage. Do not operate any electrical switches in the vicinity of the escape. Assist gas personnel, Police and/or Fire Services as requested. 8 Further Information 8.1 Graphic Representations of Gas Mains Any plans supplied or marked up by Manx Gas Ltd will indicate the APPROXIMATE location of its apparatus. This information is provided as a general guide only; its accuracy cannot be guaranteed and is given without obligation or warranty. Service pipes are not shown but their presence should be anticipated. No liability whatsoever is accepted by Manx Gas Ltd, its agents or servants for any error, omission, discrepancy or deviation. Should you require assistance on site locating Manx Gas Ltd apparatus, please contact our Dial before you dig service see Manx Gas Contact Details, page 7. KEY TO MAPS provided by Manx Gas Ltd LP: Low Pressure CI: Cast Iron MP: Medium Pressure HP: High Pressure PE Polyethylene ST: Steel 8.2 Methods of Working No work shall be undertaken near, nor heavy plant or equipment moved over, any gas pipeline or apparatus until all of the following conditions have been complied with. Where Manx Gas Ltd has apparatus in the vicinity of your work, any damage to it could have serious consequences. In view of this and in the interests of safety a meeting should be arranged before the commencement of work on site between Manx Gas Ltd representatives, representatives of the promoting authority, the contractors, and any other interested parties. At this meeting the suggested program of site works and plant safety should be discussed. It is essential that this meeting is convened well in advance of commencement on site. Access to Manx Gas Ltd plant and facilities for inspection by Manx Gas Ltd staff must not be affected. Where formal consent has been given, A MINIMUM OF SEVEN DAYS NOTICE IS REQUIRED before carrying out work in Manx Gas Ltd easements, or the appropriate notice under the New Roads & Street Works Act where existing plant is situated within the public highway. The following methods of work shall not normally be permitted within the limits of distance indicated in Table 1, (relative to the established pipe position). Any variances must have prior consent from Manx Gas Ltd: You must verify the details provided on plans by; tracing, hand digging, digging trial holes and marking their position on site, before you proceed with the work. Manx Gas Dialb4udig Procedure No. 3 - Rev 2 4

6 The Following Work Methods are not Permitted within these Distances from All Manx Gas Mains and Gas Services Excavation Distance from Pipe Mechanical Excavation Excavation by Hand Held Power Tools Other Types of Work Piling / Pile removing / Boring Welding or other hot works involving naked flame Hydraulic Testing 500mm 500mm 15m 15m 8 m Explosives 250m Table 1: Permitted distance limits for various work methods 8.3 Proximity of Other Plant No other utility should normally be installed over, below, or within 250mm to the side of the gas main. Should this separation not be possible Manx Gas should be notified and an assessment of the situation made. No apparatus should be laid over and along the line of a gas pipe irrespective of clearance. No manhole or chamber shall be built over or around a gas pipe. No work should be carried out which results in a reduction of cover or protection over a pipe without consultation with and the agreement of Manx Gas Ltd staff. 8.4 Backfill Materials The developer must ensure that any gas pipeline is surrounded by sand or other suitable material containing no stones, bricks, or lumps of concrete etc. to a depth of 150mm around the main. Backfill and sub base materials must be free from any organic, perishable or hazardous materials and is to be well compacted by hand. No power consolidation shall take place above the main until 300mm of soft fill has been compacted by hand. A gas pipe marker tape, supplied by Manx Gas, must be incorporated within the backfill for all mains and road crossing ducts and be positioned 250mm above the main or duct. 8.5 Damage to Coatings Where a gas pipe is coated with special wrapping and this is damaged, even to a minor extent, Manx Gas Ltd staff must be notified so that repairs can be made to prevent future corrosion and subsequent leakage. WHERE MINOR DAMAGE TO COATING IS REPORTED TO MANX GAS LTD STAFF PRIOR TO BACKFILL THE NECESSARY REPAIR WILL BE MADE FREE OF CHARGE. 8.6 Hot Works Even when a gas free atmosphere exists care must be taken when carrying out hot works in close proximity to gas plant in order to ensure that no damage occurs. Particular care must be taken to avoid damage by heat or naked flames to plastic gas pipes or to the protective coatings on other pipes. 8.7 Demolition Live gas services must be disconnected PRIOR to demolishing any property, arrangements must be made for Manx Gas Ltd to check for the presence of any live gas services. Manx Gas Dialb4udig Procedure No. 3 - Rev 2 5

7 8.8 Tree Planting Manx Gas Ltd staff must be contacted prior to all tree-planting works above or near our apparatus. 8.9 Deep Excavations Any work involving deep excavations (1.5m or more) will be subject to the "Model Consultative Procedure for Pipeline Construction involving Deep Excavations". This may require the diversion of Manx Gas Ltd apparatus prior to the commencement of your works. Detailed plans and cross sections will be required in order to determine the effect of these works on Manx Gas Ltd s apparatus Building Proximities There are minimum proximity distances for buildings from Manx Gas Ltd mains depending on both the operating pressure and the material of the main. Advice should be sought from Manx Gas Ltd prior to building works taking place to confirm these distances. Temporary buildings should not be placed above any gas pipe or within 3.0 metres of mains operating above 75mbar (medium, intermediate and high pressure mains) during construction activities and in no circumstances should permanent structures be built over any pipe transporting gas. 9 Site Responsibilities All costs incurred by Manx Gas Ltd for the repair of direct or consequential damage to gas plant will be rechargeable. Manx Gas Ltd reserves the right to divert any affected apparatus or alternatively specify suitable protection of its apparatus if proved necessary during the course of site works, the cost of which will be chargeable. The above requirements do not relieve you of the responsibility of taking all precautions necessary to safeguard the Company's plant and to avoid risk to persons and property. The persons for whom the works are being undertaken, their servants, agents and contractors shall indemnify Manx Gas Ltd Utilities servants, agents and contractors against any loss, damage, expenses, claims and actions incurred or brought against Manx Gas Ltd, its servants, agents and contractors in consequence of the provision of these works and activities associated therewith or ancillary thereto. Manx Gas Dialb4udig Procedure No. 3 - Rev 2 6

8 10 Manx Gas Contact Details Dial b4 you Dig Manx Gas provides a free plant protection enquiry service during office hours. (Office hours are 08:00am 5pm Monday to Friday.) Contact: Tel: dialb4udig@manxgas.co.im Fax: Manx Gas Ltd, Murdoch House, South Quay, Douglas, Isle of Man IM1 5PA Urgent out of hours Manx Gas Ltd provides a 24 hours emergency gas line Only limited information can be supplied by telephone. In general requests MUST be made in writing. For all enquires the following information is required: 1) Whether the enquiry is for speculative or actual works; 2) The full postal address of the works site and of the main company promoting the works; 3) A specific contact name and telephone number at each of these locations; 4) The full details of the nature of the works (proposed or actual); 5) The expected start date of the works and if known the duration of the works; and 6) For written enquires a suitable scale map or drawing showing the works location and any site boundaries must be provided. Don t forget there may be other services, such as electricity, water, telephone, fibre optics and drainage on your site. Contact the following for details of their plant and services. Isle of Man Manx Electricity Authority (MEA) Tel: : Fax: dialb4udig@mea.gov.im Isle of Man Water and Sewage Authority Tel: Manx Telecom. Tel: 100 T Manx Gas Dialb4udig Procedure No. 3 - Rev 2 7

9 11 Avoiding Danger from Underground Services - Summary DAMAGE TO GAS PIPES CAN CAUSE LEAKS WHICH MAY LEAD TO FIRE OR EXPLOSION CAUSING INJURY OR DEATH 1. Get a copy of the plans from Manx Gas and the other utilities, have these to hand before you start. 2. You must hand dig to confirm the exact location of all pipework & cables, whether its marked or not; service pipes are not shown on plans. 3. Do not use mechanical excavation equipment within 500mm, of the pipework. Do not follow marker tape with a digger bucket. Mains pipes may have fittings on top of the main. 4. Observe the safe digging practices as detailed in HSG47; Avoiding Danger from Underground Services. 5. If you cause any damage to a gas pipe report it immediately to Do not attempt to repair it yourself. Emergency Procedure for Gas Leaks No Smoking Call the Manx Gas 24 hour Free Emergency Number Give as much information as possible Clear the area and remove all personnel, including yourself, from the immediate vicinity of the escape. Prevent any approach by the public, prohibit smoking, and extinguish all naked flames or other sources of ignition for at least 15 metres from the leakage. Do not operate any electrical switches in the vicinity of the escape. Assist gas personnel, Police and/or Fire Services as requested. Do not use any equipment powered by internal combustion engine, or anything that may cause a spark in the vicinity of the escape. Manx Gas Dialb4udig Procedure No. 3 - Rev 2 8