Managing Health and Safety Risks during Design Stages

The design should be safe for the construction, operation, maintenance and even for dismantling of the structure (after expiry of its design life). For this, the foremost requirement is that the design should comply with applicable health and safety legislations & regulations, Approved Code of Practice (ACoP), Company's health and safety policy etc. In addition, some of the best practices which can be kept in view by the designers are given below:

• The Design Risk Assessment should be undertaken comprehensively by experienced staff member/s. The hazards and resultant risks could be identified from the previous experience, using checklists, going through the manufacturers’ (of installations) instructions, organising brainstorming sessions and risk workshops. Risk assessment is a five-step process:

1. Step 1 – Identify the hazards and those at risks.
2. Step 2 – Evaluate and prioritise the risks.
3. Step 3 – Decide on preventive action.
4. Step 4 – Take action.
5. Step 5 – Monitor and review.

• The Risk Register should be maintained and updated on regular basis, as design progresses through different stages (e.g., concept, preliminary & detailed) and more information is received from the site surveys/investigation, testing etc.
• Written information should be provided along with the design drawings drawing attention towards potential hazards and risks.
• ‘SHE’ box should be incorporated on the drawings embodying significant potential hazards relating to safety, health and environments during construction on the site, as it has been observed that the drawings are more frequently used by the construction staff than scanning the risk register and other documents used for indicating potential hazards during construction.
• Construction sequence could be prepared and communicated to the construction teams in writing.
• On the highway projects, Road Safety Audits should be undertaken at different stages, and the recommendations of Safety Audits should be seriously considered, as they are meant for the safety of end users.?
• Position of structures should be selected keeping in view the risks from site hazards, such as buried services, overhead powerlines, traffic movement to, from and around the site, contaminated ground etc.
• The processes that create hazardous fumes, vapours, dust, noise or vibration should be avoided. Lighter materials should be specified that are easy to handle. Mechanical handling should be recommended for the heavier materials such as concrete flags used for paved areas.
• The safety hazards should be designed out by eliminating or minimising the need for work at height, particularly where it would involve work from ladders, or where safe means of access and a safe place of work is not provided. Eliminate fragile roofing materials, reduce the need for deep or long excavations in public areas or on highways, minimise materials that could create a significant fire risk during construction, etc.
• Consider prefabrication to minimise hazardous work or to allow it to be carried out in more controlled conditions off-site, such as designing such that structural steel and process plant can be assembled at ground level and then safely lifted into place, arranging for cutting to size to be done off-site, under controlled conditions, to reduce the amount of dust released, etc.
• Design features that reduce the risk of falling/injury, where it is not possible to avoid work at height, including early installation of permanent access, such as stairs or reduce the use of ladders, provision of edge protection or other features that increase the safety of access during construction, etc.
• Design to simplify safe construction, by providing lifting points and mark the weight, and centre of gravity of heavy or awkward items requiring slinging both on drawings and on the items themselves, make allowance for temporary works required during construction, design joints in vertical structure steel members so that bolting up can be done by someone standing on a permanent floor, and by use of seating angles to provide support while the bolts are put in place, design connection to minimise the risk of incorrect assembly etc.
• Design to simplify future maintenance and cleaning work, by making provision for safe permanent access, specifying windows that can be cleaned from the inside, designing plant rooms to allow safe access to plant and for its removal and replacement, providing safe access for roof-mounted plant, and roof maintenance, making provision for safe temporary access to allow for painting and maintenance of facades, etc.
• Identify demolition hazards for inclusion in the health and safety file, such as sources of substantial stored energy, including pre or post-tensioned member, unusual stability concepts, alteration that have changed the structure etc.
• The HSE, UK has published on their website a red, amber and green list for designers based upon work undertaken by various consultants. This list should be kept in view by the design team.

In addition, following are the general principles which could be adopted during design and construction stages to combat risks. A few examples are provided under each principle as well:

1. Avoiding risks:

• Block-laying involves repetitive lifting actions. Lifting dense heavy blocks can cause musculoskeletal problems. The risk of injury can be reduced by specifying alternatives such as smaller or lighter blocks.
• There are hazards from entering confined spaces in sewage treatment plants such as underground chambers associated with surface and foul water systems. However, if the design is changed so that such places are open to the general atmosphere and well ventilated, those hazards will not be present.

2. Evaluating the risks which cannot be avoided:

As mentioned above, a structured approach should be taken to evaluate/assess risks.

3. Combating the risks at source:

• Dust created during demolition can cause a number of hazards. It may be harmful if inhaled and it may reduce visibility. The water-sprays directed on work surfaces help to prevent dust clouds forming.
• Wood dusts can be harmful if inhaled. Provide circular saws with mechanical dust extraction systems so that the dust is immediately captured at the point of creation.
• During the design of a new multi-storey apartment building, it was decided that prefabricated flights of stairs should be included so that suitable safe access would be available at the earliest opportunity. (It also led to a shorter erection cycle for each storey.)

4. Adapting the work to the individual:

• Reduce the weights of cement bags and aggregate, that are supplied to a project, so that the likelihood of injury is reduced.
• Significant runs of parallel pipe work had to be installed at a high level in a complex building. The contractor recognised that overhead working at height would create risks and decided to prefabricate cradles supporting sections of completed pipe work. Special trolleys with hydraulic lifting devices were used to raise the cradles and to provide working platforms during installation.
• A theatre auditorium had a number of large, high-level lighting clusters in inaccessible positions. Motorised systems were installed that allowed the clusters to be lowered so they could be safely cleaned and maintained.

5. Adapting to technical progress:

• Work in confined spaces may expose people to non-respirable atmospheres and toxic and flammable gases. In past, monitoring equipment was expensive and required a high degree of expertise to use it. Now, multi-function gas detectors are much less expensive and can be effectively used by most workers. Also, new technology has led to video systems that can remotely inspect confined spaces such as sewers.
• Mechanically compacting fill materials in trenches can cause health problems due to hand-arm vibration. Nowadays, radio-controlled compactors are available that remove the hazard.

6. Replacing the dangerous by the non-dangerous or the less dangerous:

• There may be instances where mechanical fixing systems reduce the overall risk when compared to alternative chemical fixing systems.
• When doing painting works, substitute water-based paints for those that contain harmful solvents.
• In road works, use low-temperature asphalt helps to prevent exposure to toxic substances.
• When tunnelling using sprayed concrete linings, a wet mix was specified rather than a dry one so as to reduce dust. Before work started, the designer advised the client that more time would be needed to allow for trial mixes and for spraying test panels before the tunnelling started but the benefits of using new technologies were significant.

7. Developing a coherent overall prevention policy:

It deals with the organisation of work, working conditions, social relationships and the influence of factors related to the working environment.

In order to control risks, the whole safety system needs to be considered: the individual, the task, the plant and equipment, the management organisation and arrangements of the various stakeholders and the management of the whole project, the wider environment and how they interact. Technology, ergonomics and the human sciences can contribute in developing a preventative strategy.

It is important not simply to focus on the immediate hazards that are common to the industry. There is equally a need to identify the underlying factors that cause injuries. These are invariably associated with the culture in the organisation or on the project. This strongly influences the attitudes and behaviour of everyone involved.

How and why people make errors and why people deliberately fail to do what was required of them (violations), can raise complex issues.

Errors can be reduced by providing a good working environment and addressing:

1. Extreme task demands (high workload, high alertness, time pressure);
2. Social and organisational stressors (staffing levels, conflicting attitudes);
3. Individual stressors (training, experience, fatigue); and
4. ‘Equipment’ stressors (controls, instructions, procedures).

Human violations can be reduced by a positive safety culture which includes:

1. involving the workforce.
2. improving the working environment.
3. having rules that are relevant and practical and explained to those who have to follow them.
4. providing the necessary work equipment.
5. improving relationships between people.
6. improved job design and planning.
7. improved supervision and monitoring.
8. reducing time pressures.
9. avoiding alcohol, drugs and substance abuse.

8. Giving collective protective measures priority over individual protective measures:

• A guard rail at the edge of a working platform protects everyone from falling and requires no action by the workers who benefit from it. Safety harnesses require individuals to make use of them, they need suitable anchorages, and fall arrest devices that must be available and suitably maintained. Harnesses often create considerable practical difficulties in their use. Hence, the likelihood of harnesses achieving the same degree of success as a guard rail in preventing injuries is small.
• The designer added a parapet to the perimeter of a flat roof so that there would be permanent protection for everyone working on the roof throughout the lifetime of the building. A system of using harnesses and anchorages was ruled out on the grounds of continuing maintenance costs and the limited protection provided.
• A contractor clads the facades of a major scaffold in protective sheeting so as to prevent falling material causing injury. (The enclosure also enabled work to continue in reasonable comfort during adverse weather)
• When constructing the cantilevered deck of a high bridge, safety nets were installed under the false work to catch falling materials. This collective protective measure reduced the falling material risk to everyone below the bridge.

9. Giving appropriate instructions to the workers.

Few examples are:

• Common induction sessions for all new workers prior to starting work (there are a number of common matters that workers new to a project need to know).
• Further instruction by trade contractors before their workers start a new task and daily reminders before work start.
• Routine toolbox talks.
• Keeping records of workers’ training and their presence at induction sessions.