Mark Da Silva addresses the key issues of working at height.
The fundamental requirement of any business these days is to provide a safe work environment. It makes good business sense, because surely shareholders would not invest in a company that injures its people, right? When you think of occupational safety you may think, “I’m safe, but is my workplace safe? What are the potential hazards in my workplace?” Height safety is often over looked as just one of many potential hazards.
From climbing ladders and stairs to tripping on a step or falling into a ditch, height safety covers any height, however small and insignificant it may seem. If there are potential height safety hazards in your workplace, they can be grouped into the following three categories:
• Falls from height – a fall from one level to another
• Falls into a depth – falling into a hole
• Slips, trips and falls – falls on the same level
Height safety may be a potential hazard in your workplace and so a holistic approach should be taken, from the initial inception of a design, the development of construction and the operability phase, through to the decommissioning stages at the end of a life cycle. In all of the areas previously mentioned, forethought must be given to the end user at every stage for a safe system of work to be implemented.
Where there is a risk of falling, employers must protect workers by providing:
• A safe system of work, such as anti fall equipment and devices
• A safe means of entering and leaving the area in which employees are required to work
• Guard rails, covers, fender boards or other forms of safeguarding workers at height
• Personal protective equipment (PPE)
In analysing a productive and safe system of work programme for height safety, there are two key objectives to reflect upon: the ‘safe place’, and the ‘safe person’. From the ‘safe place’ objective there are two essential areas which relate directly to place and plant – these are substitution and engineering/isolation.
Substitution and engineering/isolation are more significant in increasing effectiveness and sustainability on the hierarchy of risk controls when compared with place and plant, where an increase in participation and supervision is required and almost leans towards behavioural based safety, where the ‘safe person’ is involved. In organisations bound by safety rules and guided by polices and procedures, effective use of protection such as PPE is implemented, which relies heavily on the ‘safe person’ doing the right thing.
This can include, for example, a worker clipping onto a static line when working at a height where they may be exposed to an edge. This is used to prevent the person from going over the edge, and is more commonly known as fall restraint. If the person was to wear a harness for the same activity, but to prevent a fall of more than two metres, then this may be considered as fall prevention. On the contrary, if the lanyard is three metres in length and longer than the fall height of two metres, this will make wearing the harness unnecessary and defeat the purpose. In the event of a fall the person will hit the ground. Another issue occurring in a fall from height is known as the ‘pendulum’ effect, where the person falls and swings from side to side.
These four elements are paramount when working at any height in the context of fall prevention. Some examples of working at height activities may include working on building roofs and using mechanical intervention to reach a certain height; for instance, by using elevated work platforms like scissor lifts and knuckle or boom lifts.
Other height access equipment such as scaffolding is built to gain temporary access at height, with the most common equipment used for height work being a platform or step ladder. Conversely, falls into a depth, such as work in the construction and excavation industries, are often caused by trenches or holes that are hazardous if left unprotected. Falls into lift shafts, sewers, wells, tanks and stairwells are examples of falls into a depth.
Signs should be used to warn anyone on the site that there is a hole underneath, and that the cover should not be removed. Covers should be securely fixed and marked in clear lettering:
DO NOT REMOVE – HOLE UNDERNEATH
As with all types of equipment used for height safety, it must be fit for purpose. Workers must ensure they are competent in using the required tool, plant or equipment to prevent falls. Where that is not practicable, fall restraint or fall arrest devices may be used, but only as the last resort. Overall, the best outcome for height safety is adopting the hierarchy of risk control approach, namely, aiming for elimination. This is where a working at height activity can instead be completed at ground level; for example, a roof being constructed on the floor and craned into place.
Before any height work occurs it is proactive to assess the scope of the works, by job walking and inspecting the work area for potential hazards, not only working at height issues, but secondary risk factors as well. If you use a mobile crane to lift a man box into position, the mobile crane may create a traffic hazard. When assessing the workplace, the area or location of the activity, such as where to safely position the crane, is an important element to consider. Another key factor is the safe access and egress of walkways, including pedestrian pathways and workways for heavy vehicles and mobile plants around the work site.
Regarding primary risk factors, fall prevention strategies including constructing roof guarding, installing anchor points or placing static lines at the top of the building structures ensure safe rope access for people working at height.
Many falls from and through roofs occur during maintenance, renovation and cleaning work. Roof edges should be guarded to prevent falls due to overbalancing.
Some materials used on roofs can become fragile or brittle after being exposed to the elements. Serious injuries and fatalities have occurred when workers have fallen through roofs made of brittle materials such as asbestos cement sheets, translucent plastic sheets and glass skylights. Safety in this regard should be simple – you must not stand on or walk across a roof made of fragile materials.
Work on fragile material must be done from a scaffold or other working platform. This must be done even if mesh has been installed. To ensure people are aware of the hazard, the following notice should be displayed:
DANGER FRAGILE ROOFING USE WORKING PLATFORM
The use of protective wire mesh is compulsory for roofs made of brittle materials and is also recommended during the construction of metal roofs. Protective wire mesh protects workers from falls during roof construction and provides protection for future work activities on the roof. Before working on brittle roofs, the wire mesh and sheeting must be checked to see if it is safe to use. In addition to the use of steel mesh, harnesses, nets and guard rails will also restrain a fall.
Anchorage points must be routinely inspected and placed above an area where works are being done. If the load bearing point is impaired, either remove it or otherwise place a danger tag on it and notify a supervisor or delegated management representative.
Another key element when assessing height safety is plant. Typically, plant and equipment may involve the use of mechanical devices such as elevated work platforms. Such items of plant are commonly referred to as scissor lifts, boom lifts and knuckle lifts.
The purpose of the relevant plant and equipment used to reach a nominated height is to make the height easily accessible, while ensuring safe containment within the cabin area by restricting the movement, or reach envelope of a person. Any movement or body part outside the perimeter area of the restricted barriers, such as leaning outside or persons standing on mid rails, is not the intended purpose for which working at heights plant and equipment was specifically designed, and is considered unsafe.
Plant height safety considerations extend to the safe use of scaffolds, in particular the erection, alteration or dismantling of temporary structures that are specifically erected to support platforms higher than three metres. Items of plant and equipment should be inspected regularly.
People who erect and install scaffolds are responsible for ensuring that the scaffolding is safe and won’t endanger anyone if it is used according to safety instructions.
Mobile scaffolds are often hired and used by finishing tradespeople such as painters and plasterers. Mobile scaffolds are easy to put up, use and take down, but are safe only if they are erected by a person who knows what they are doing.
Supervision should be provided on any site to make sure that scaffolding is erected properly with the correct guard rails.
Guard rails can prevent falls from a working platform. Common problems occur with mobile scaffolding when:
• There is not enough training, supervision or instruction in erecting or using a scaffold
• Riding on a mobile scaffold while it is being moved
• Wheels are not locked when the scaffold is stationary
• Access ladders are not placed on the inside of the scaffold
Mobile scaffolds can be easily overturned because they are light. Climbing on the outside of a mobile scaffold can cause it to overturn.
Instructions on the safe assembly of a mobile scaffold are available from the supplier. These instructions are also displayed on most mobile scaffolds as a sticker. It is very important that these instructions are followed.
To avoid hazards related to working at height, be mindful of:
• Tying off tools with lanyards
• Constructing toe boards so tools do not fall
• Installing barricades to prevent people walking into the line of falling objects
• Displaying signage at access and egress points to alert personnel of work being conducted above
As part of a height safety risk management strategy, thought should be given to the adoption and practise of an emergency rescue plan. A working at height checklist should also be completed to assist in the identification and control of hazards and risks associated with working at heights.
All scaffolds should be erected by a competent person who has completed an industry recognised training course. Persons erecting scaffolds should use a fall prevention system in situations above two metres, where it is not possible to maintain three points of contact with the scaffold, such as when using two hands to perform work.
Incomplete scaffolds should have barriers erected on the access points and ‘Out of Service’ tags should be placed on each such barrier.
Persons working from scaffold platforms should not leave the confines of the platform edge protection without a fall arrest system.
Mobile scaffolds may be used where it is not practicable or economical to use fixed scaffolding, or as determined by the risk assessment. A mobile scaffold height is restricted to nine metres and the height must not be more than three times the least base dimension.
Mobile scaffolding should be used when:
• There is a requirement for regular movement of the working platform
• The supporting surfaces are hard and level
• Stationary and the castors or wheels are locked
Only a specially authorised person with an advanced scaffolding certificate (or equivalent) should erect suspended scaffolds.
When using any working at heights plant there are a number of activities that should be completed to determine potential hazards. Check the plant log book for the condition of the item, as previous use may require maintenance to check and verify that the plant and equipment are fit for purpose. Prior to using the plant and equipment, the manufacturer’s instruction manual should be read to ensure correct use. This may also include reading a plant risk assessment to ascertain all risk controls have been safely implemented and the person using the plant feels it is safe to proceed.
The next activity may involve consultation with the work crews and supervisors. This is to ensure the process is being followed correctly, such as using safe systems of work that may examine management plans and risk registers, as well as following site operating work instructions and procedures. If all personnel involved in the height work have completed a safe work method statement, risk assessed the working at heights activities and planned the work correctly, they will be able to work the plan correctly.
The human factor
The next key aspect examines the ‘people’ element. Workers must be appropriately trained in working at heights activities. Additionally, if using height safety equipment then employees must be competent in erecting and dismantling the scaffolding. For those workers using PPE, fall arrest devices should only be enabled when fall prevention cannot be achieved. Also, rescue equipment must be readily available when a fall arrest device is used, which may include first aid.
To prevent material and items of plant and equipment from falling, other materials can also be utilised such as catch nets, blankets and tool lanyards. Consideration of adopting PPE must also ensure that training in selection and assembly when using arrest devices will be adhered to, as per manufacturers’ specifications. A visual inspection check is also warranted to check for any wear and tear, cuts or abrasions that may reduce the quality of the product. Moreover, to ensure the safe system of work is adhered to, managers must reinforce awareness and check training records to ensure personnel are competent to perform work at height activities.
Protection is the last element that involves the function of the ‘safe person’. The fall protection equipment must be tested and certified for use, continually maintained and inspected before use. Conversely, any material used for work at height that is neither satisfactory nor fit for purpose should be destroyed. This is of particular importance following a fall, excessive wear and tear or mechanical malfunction.
If there is a person ascending to or descending from height, there must also be a rescue plan included. This should be practised before working at height. The testing of emergency procedures ensures that any life threatening injuries can be dealt with effectively and efficiently. The rescue plan should enable the person to be removed from the suspended position as quickly as possible to prevent the fallen person developing suspension trauma.
The most common equipment used to work at height is the ladder. A planned pre-start check of the equipment is required to ascertain its fitness for purpose. This is conducted by completing a fall prevention risk assessment. In addition to following manufacturers’ guidelines and instructions, a great enabling tool to use in deciding whether equipment is safe to use is a pre-qualification checklist. This outlines what to use and when, determining and identifying hazards directly related to height safety for plant, equipment or ladders.
In some cases where fixed ladders extend more than two metres in height from the ground, ladder cages have been installed to prevent persons from losing balance and falling backwards. Alternatively, if mobile and fixed ladders are used these should be checked and inspected regularly as part of a maintenance regime.
Platform ladders are commonly used in construction for most trades such as mechanical fitters and electricians. These also need to be inspected regularly, before and after use.
The available studies exploring the risk factors implicated in ladder fall incidents focus largely on Swedish and American data. Hakkinen et al (1988), estimate that ladders are involved in one or two percent of all occupational injuries in industrialised countries. In a regional study of falls based on Swedish hospital data, Bjornstig and Johnsson (1992) reported that 32% of the cases were work related (Field et al, 2000).
An adequate ladder inspection checklist provides early hazard identification and can be utilised as an administrative risk control.
These controls may include:
• Inspecting the ladder for defects before use
• Following manufacturer’s guidelines for inspection
• Removing ladders with structural defects
• Keeping ladders secured and barricaded
• Storing ladders in a rack or chain to wall so that they cannot fall
• Inspecting ladders immediately after tip or fall
In summation, adopt the hierarchy of risk control for height safety. This is the first protocol of engagement when planning any work at height. Ensure you can eliminate the hazard by:
• Completing the task at hand on the ground or on a solid construction
• Using a passive fall prevention device, e.g. a temporary work platform
• Using a work positioning system, e.g. travel restraint system
• Using a fall injury prevention system, e.g. harness and lanyard
• Using a ladder or administrative controls
Published: 11th Oct 2013 in Health and Safety Middle East