Safe Digging Guidance (HSG47)
This guidance outlines the potential dangers of working near underground services and gives advice on how to reduce the risks.
Underground Services: The Dangers
Damage to underground services can cause fatal or severe injury as well as significant disruption and environmental damage. It can also delay the project and incur considerable costs.
Working safely
A safe system of work has three basic elements:
· Planning the work.
· Detecting, identifying and marking underground services.
· Safe excavation/safe digging practices.
When carrying out excavations, it is important that;
· Those supervising and carrying out the work have sufficient skills, knowledge and experience to do so safely.
· Safe working practices are put in place and used.
· Appropriate traffic signing is used on highways. (This is described in Safety at street works and road works.)
· Risks from other sources, such as collapse of excavations, are avoided.
Planning The Work
Identify clearly the extent of the work area and find out what underground services are within the area before considering whether they are likely to be disturbed:
· Obtain service drawings from utilities companies and other organisations with relevant information about the site.
· Survey the site to identify the services and other underground structures. Record the location of any services.
· Review/assess the planned work to avoid disturbing services where possible.
· Allow sufficient time and provide sufficient resource to do the work safely.
· Emergency work still requires planning and assessment of the risks arising from the work. A precautionary approach must be taken when breaking ground.
Detecting, Identifying and Marking Underground Services
Locate the services identified at the planning stage survey as being in the work area. Make sure those involved in detecting and identifying services are competent in the proper use of survey tools and detecting devices as well as reading/interpreting plans. Once detected, identify and mark the services and confirm their status – i.e. whether electricity cables are live, whether gas pipes are pressurised – and then record their location.
Safe Excavation
Determine the method or technique for excavating near underground services before work starts, taking account of:
· The nature and scope of the work.
· The type, position and status of underground services.
· The ground conditions.
Identified services should be carefully exposed and clearly marked. Backfilling of excavations must properly support and protect the underground services. If an underground service suffers damage during the excavation or subsequent work, inform the owner/operator. In the case of electricity cables, gas pipes, other pipelines or high-pressure water mains, arrange to keep people well clear of the area until it has been repaired or otherwise made safe by the owner/operator. In addition, you should also continue using the CAT/GENNY minimally every 300mm of excavation, this will assist in the location of underground services whilst excavating is being completed.
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Every civils team must complete the Mia Direct Utility Avoidance electronic form for every duct section they dig on, the form is designed to assist you in ensuring you are carrying out safe digging techniques. The link for the form has been sent to every civils engineer, if you do not have the link then contact your direct line manager immediately, the completion of these forms will be monitored.
All civils engineers must be able to read and understand utility prints / stats. If you have any issue with reading these stats, or if you have any eye issue that prevents you from reading the stats, such as colour blindness, then contact your direct line manager immediately.
Finally, for all engineers, you must complete a Point of Work Risk Assessment (POWRA) for every job you complete, this means you may need to complete several POWRA per day, dependant on the work being carried out. The link for the form has been sent to every engineer, again if you have not received the link, or if you have any queries, then please contact your direct line manager or the Health and Safety team immediately.
Gas Detection Unit (GDU)
A common near miss within our industry is where gas is detected in chambers, street furniture & excavations. It is imperative that the GDU is utilised correctly & when required (as per SA002 Safety Underground and K8 Hand Rodding in the underground network accreditations).
Mia Direct operatives, including contractors, must be fully aware of their responsibilities when utilising a Gas Detection Unit (GDU) & have sufficient knowledge of testing procedures.
Testing for gaseous vapours, including oxygen deficient atmosphere, is an integral part of health & safety legislation adopted within the telecommunications industry to safeguard company personnel & the general public.
Operating the GDU
· Slightly open the apparatus (joint box/chamber/cab) & perform the initial test (30 seconds or 3 bleeps).
· Fully open the apparatus & test at the top, middle & bottom, for a period of 30 seconds or 3 bleeps at each position (gases have different densities).
· Test all duct entries for 30 seconds or 3 bleeps (at the point where each duct enters the apparatus).
· If the apparatus contains residual water, test at water level for 30 seconds or 3 bleeps & break the surface of the water to release any gaseous vapours (sewage).
To test confined or enclosed spaces, perform the testing procedure before entering. If tests prove clear, continuously monitor until the activities cease. N.B. Only personnel who hold a confined space training qualification are permitted to enter any chambers categorised as being a confined space.
The GDU should remain switched on & in situ for continuous testing for the duration of the works being undertaken.
The GDU must be fully charged at the start of each working day & maintain sufficient charge to conduct daily working activities, non-compliance may result in disciplinary action.
If the GDU is not calibrated, or close to the required calibration date, then contact your direct line Manager, Warehouse Manager or the Health and Safety team immediately.
If the GDU alarms whilst testing and after venting, then contact your direct line manager immediately.