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Subsurface Networks
For hundreds of thousands of years, our natural domain has been a principally two-dimensional space: the surface of the ground. Urged by necessity, curiosity, and even by temerity, we have always tried to escape from this space, either by widening it, which is only possible in a very restrictive sense, or by searching to utilize the third dimension, upwards or downwards. In these efforts, we have always encountered great difficulties that have been overcome thanks only to an astonishing tenacity. So it has been and so it still is in the conquest of the continents, the oceans, or outerspace. So it is for the use of underground space. In this field, as in the others, nature provides many challenges and we must doggedly gather our experiences, draw lessons from failures, improve techniques and use all our resources of inventiveness before succeeding. for more details
HAZARD IDENTIFICATION FOR SUBSURFACE NETWORKS
In this chapter we are discussing the issues related to the Hazard Identification related to the activities of Subsurface Network Development and Management.
As discussed earlier hazards in subsurface networks are contributed from four identified sections, excavation and backfilling, confined space working, equipment operations, and roadworks. To manage such hazards the first and foremost activity is their identification, i.e. identifying possible hazardous situations in these activities. A detailed discussion about their assessment & control will be done in the relevant chapters subsequently. In this chapter we are discussing the issues related to such risk identification. for more details
ASSESSMENT OF EXCAVATION HAZARDS
Excavation is defined as any man-made cut, cavity, trench, or depression in the earth’s surface formed by earth removal. This can include excavations for anything from cellars to highways. A trench is defined as a narrow underground excavation that is deeper than it is wide, and no wider than 15 feet (4.5 meters).
Trenching and excavation work presents serious hazards to all workers involved. Cave-ins pose the greatest risk and are much more likely than other excavation-related accidents to result in worker fatalities. Other potential hazards include falls, falling loads, hazardous atmospheres, and incidents involving mobile equipment. for more details
ASSESSMENT OF HAZARDS OF CONFINED SPACE WORKING
Having assessed the excavation hazards the next step in the hazard management process is the assessment of confined space working hazard. Confined spaces in subsurface networks are encountered at several occasions, while developing networks, as in the case of deep shafts, trenchless laying of large diameter pipelines or as in the case of renovation or renewals of man-entry networks. Confined Space Confined space is a space that, by design and/ or configuration has:
These hazards are again one of the most deadly hazards in the construction industry and proper care for them is more than necessary. for more details
RISK ASSESSMENT FOR WORKING WITH EQUIPMENT
Risk assessment of equipment operations is a vital part of the hazard management process as in this case the power generated by the equipment, both the thrust as well rotary have the strength to kill or maim people and the hazard control in this case has to done carefully.
This chapter deals the issue of assessment of hazard related to the equipment related to the subsurface network development.
Hazardous Mechanical Motions and Actions A wide variety of mechanical motions and actions may present hazards to the worker. These can include the movement of rotating members, reciprocating arms, moving belts, meshing gears, cutting teeth, and any parts that impact or shear. These different types of hazardous mechanical motions and actions are basic to nearly all machines, and recognizing them is the first step toward protecting workers from the danger they present. The basic types of hazardous mechanical motions and actions are: Motions · rotating (including in-running nip points) · reciprocating · transverse Actions · cutting · punching · shearing · bending for more details
ASSESSMENT OF ROADWORK HAZARDS
Roads and highways can be dangerous. Each year about a large number of highway construction workers get hurt or sick. A percentage of these highway construction workers are killed on the job. Parts of such hazards are due to the issues discussed till now. These include hazards due to excavation, confined space working, and mechanical working. When these are combined and mixed with the external hazards due to presence of unconnected persons or incidents or other factors, hazards related to roadwork come into play. The combination naturally becomes more lethal and the Hazard management in turn more complex. Through this chapter we are discussing the issues related to the assessment of hazards associated with roadworks.
The chapter also recalls the previous chapters so that the magnitudes of mixed hazards are better explained. Say, for an example a water mains is damaged due to excavation and the road surface in turn collapses the resultant hazard develops due to coupling of two independent hazards, excavation and utility damage. Now if in the same scenario a electrical cable is introduced and the soil shift damages this cable the complexity of the situation goes up. Issue may not stop there as there is a very high likelihood of the presence of a gas pipeline or petroleum or an oil pipeline in the same excavated section leading to a subsequently more hazardous situation.for more details
EARTHWORK HAZARD CONTROL
Before excavating activities actually begin, the location of buried facilities that may be encountered during digging must first be located. Buried or underground facilities include anything below the ground that transports or stores products and services such as:
These facilities may be contained in pipes, conduits, ducts, cables, wires, valves, manholes, catch basins, storage tanks and attachments associated with these items. Striking any of these facilities could result in personal injury and injury to other workers, electrocution, explosion or the release of a harmful substance(s). In addition to these health and safety consequences, vital services may be disrupted and repair costs may be incurred. for more details
CONFINED SPACE WORKING HAZARD CONTROL
Hazard Control
Design and Manufacture of Systems or Plant which includes a Confined Space
The design of plant which includes a confined space, such as a boiler, vat, tank or duct is critical. Thoughtful design can avoid hazards and eliminate or reduce many of the risks associated with work in the confined space before it is introduced into the workplace. All phases of the life of plant, from design and use through to demolition and disposal, should be considered when designing plant which includes a confined space. Modification of existing plant which includes a confined space is also covered under this regulation.
The Regulations do not mandate that designers or manufacturers undertake a hazard identification and risk assessment process. However, in complying with the duty to control the risk, designers and manufacturers may take steps to identify any hazards and assess risks associated with the confined space to assist determination of appropriate risk control measures. For example, hazards arising out of:
EQUIPMENT HAZARD CONTROL
The next part of the hazard management process is the control measures for the equipment hazards. Equipments, at one hand provide sufficient strength so that all such work which is humanly not possible could be accomplished, at the other had also develop situations which can be disastrous for the workmen, the local environs, and habitat.
Here is the role of the hazard manager who has to manage hazard at one hand and get the work accomplished at other hand. When a subsurface network is developed or managed most of the time quite powerful equipments are used. Take for an example, a sewer cleaning jetting system which uses a thrust of 20,000 psi jet to break throws the cleaning hammer on the accumulated scum. For the uninitiated a pressure of 20,000 psi is so strong that it can be used to break an RCC slab and if this is used in the sewer line without proper safety measures or controls imagine the kind of hazard it could create.for more details
ROADWORK HAZARD CONTROL Key Question
Ask yourself this question: Will someone coming along the road or footway from any direction understand exactly what is happening and what is expected of them?
Other Physical Hazards
Imagine ground water percolating or seeping in a road trench. What is expected in this case? First the trench will be inundated with the ground water and if he flows are higher flooding will occur. Presence of this water in large quantity will moisten the sides of the trenches allowing them to slip in the trench thereby developing a situation of road settlement which in turn can lead to serious accidents. Now if the area cordoning is planned and executed properly and soil settlements are noticed in time to shift the cordons to subsequent safer locations some of the possible accidents can be avoided. But if water pumping is also being done another solution would be to increase the rate of this suction to match the percolation.for more details
EMERGENCY PREPAREDNESS FOR SUBSURFACE NETWORKS
EMERGENCY PROCEDURES
Before operating any equipment, review emergency procedures and check that all safety precautions have been taken.
Emergency Shutdown
Turn ignition switch to stop position or push remote engine stop button.
Electric Strike Description
When working near electric cables, remember the following:
PROTECTING ROADWORK
Today’s roads are full of fast, heavy traffic. Drivers have to keep a constant look-out for changing road conditions. Whilst this code is primarily directed at you the operative, supervisors and managers have an important responsibility to make sure that all street and road works and operatives are safe. Road users should not be put at risk, and should be informed well in advance about the size and nature of any obstruction. This applies to vulnerable users – including pedestrians, cyclists, motorcyclists and horse riders – as well as drivers.
You must also pay particular attention to the needs of blind and disabled people, children, elderly people and people with prams.
SITE LAYOUT
What is the works area? The works area is the excavation, chamber opening, etc, at which you will be working.for more details
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