Hazards and Hazardous Environments

Confined Spaces

Entry into a confined space can be one of the most hazardous activities, which you as a construction worker may be faced with.

Be aware of the confined spaces that may exist on site.  Generally they will be areas with limited openings for workers to enter and exit and are not designed for regular occupancy.  There may be areas that contain or cause an accumulation of atmospheric hazards.  They may also have a deficiency or over supply of oxygen.

Confined space entry is a specialised field requiring detailed training and a thorough understanding of the appropriate work and safety practices.  Don’t attempt to enter a confined space unless you are fully trained and know what you are doing.

Further requirements include a written authority to enter, risk assessments, rescue and first aid procedures.

Examples of confined spaces:

• Trenches and excavations
• Ceiling work
• Life wells
• Stairwells
• Tunnel construction
• Asbestos removal
• Basement areas of buildings under construction
• Caisson
• Underpinning

Major hazards of working in confined spaces:

• Oxygen deficiency
• Presence of atmospheric contaminants
• Accidental operation of machinery, services
• Performance of non-routine tasks

Control Strategies:

• Personnel, training, rescue and first aid
• Entry procedures including:
• Preliminary review
• Safety of the atmosphere
• Authority to enter a confined space
• Determine whether there is a need for a person/s to work in or enter a confined space
• Consider substituting the work or process with one less hazardous
• Changing the process so that the work may be performed without need to enter a confined space
• Engineering in controls to separate the worker from the hazard
• Determining if there is a need to set up training, maintain supervision, develop rosters, etc.
• Does the work require PPE
• Additional precautions during occupancy:
• Staffing
• Use of portable electrical equipment
• Static electricity
• Suitability and safety of non-electrical equipment
• Approval for return to service

Fatigue

There are serious consequences potentially in fatigue related incidents.  Our fatigue policy which requires in general that within a 24 hour period, Sub-Contractors must take a break of at least 10 hours in a continuous block.  This break cannot be made up of smaller periods but must be continuous.

Working Outdoors

Effects of the Sun

We are becoming more aware nowadays of the need to stay out of the sun because of the damaging effect the suns rays has on our skin.  Australia for instance has the highest incidence of skin cancer in the world and the number of reported cases of skin cancer has increased alarmingly over the past years despite increased awareness of the problem. 

The effects of the sun are cumulative so it is important to encourage lifelong habits of avoiding overexposure at an early age.

Skin cancer is very visible, so it can be detected early.  Early detection leads to a complete cure in most cases with minimal disability. 

The Causes Of Skin Cancer

Ultraviolet light is the major cause of skin cancer. 

There are three different types of ultraviolet rays:

• Ultraviolet A.  These rays primarily cause ageing by sun exposure.  The rays are prevalent throughout the day and shine all year round being as abundant in winter as summer.  The rays are very strong regardless of where you live.
• Ultraviolet B.  These rays are responsible for sunburn and skin cancer.  The rays are most abundant between the hours of 10.00am and 3.00pm when the rays are at the shortest distance to the earths surface.  Those rays are also most intense closer to the equator.
• Ultraviolet C.  These rays are not of particular concern as they are trapped by the ozone layer, however if the ozone layer continues to be depleted then they will pose problems.

Types Of Skin Cancer

There are three main types of skin cancer:

• Basal cell carcinoma
• Squamous cell carcinoma
• Melanoma

Preventing Skin Cancer

There are a number of things we can do to protect ourselves from the harmful effects of sunlight:

• Stay indoors during the middle part of the day when the ultraviolet light is at its peat.
• Sporting activities should be scheduled either early morning or late afternoon.
• Physical Shade
• Wear broad-brimmed hat
• Wear protective clothing
• Wear broad-spectrum sun cream/lip zinc
• Wear sunglasses

Heat illness

Heat exhaustion:  occurs when the worker becomes slightly dehydrated due to the constant loss of water in perspiration.  Replacement of the water loss usually promotes a full recovery.

Heat Stroke:  is a potentially irreversible and fatal response to exposure to extreme heat when the body is unable to maintain its normal regulation of temperature.  Early warning signs need to be recognised. 

These include:

• Headache
• Nausea
• Dizziness
• Pale, cool skin initially, later becoming red
• Rapid and weak pulse.

Management includes:

• Replace lost fluids
• Rest in cool, shaded area
• Ice packs to wrists, groin and neck region
• Monitor and seek medical attention if heat stroke is suspected.

Protection from heat will include:

• Wear long sleeve shirts
• Long trousers
• Head and neck protection
• Maintain fluid intake

Noise

What Is Noise

Noise is unwanted sound that may damage a person’s hearing.

Sound Waves

Sound pressure is measured in decibels (dB).  The decibel scale is logarithmic, or compressed, as the human ear is capable of hearing a broad range of sound pressures.

The amount of damage caused by noise depends on the total amount of energy received over time.  This means as noise becomes louder, it causes damage in less time. 

Excessive noise is defined in the [e.g. your state Health Regulations] and means a level of noise above

• LAeq, 8h of 85 dB(A) – that is, an 8 hour equivalent continuous A-weighted sound pressure level of 85 dB(A), referenced to 20 micropascals; or
• LC, peak of 140 dB(C) – that is, a C-weighted peak sound pressure level of 140 dB(C), referenced to 20 micropascals.

What does L Aeq, 8h of 86 dB(A) mean

LAeq,8H of 85 dB(A) means the actual energy of varying noise levels experienced over a period is equivalent to 8 hours of a continuous steady A-weighted sound pressure level of 85 dB(A).

In simple terms, this can be shown in the following table which has a range of time/sound level variations equivalent to a daily noise dose. 

For example, a person exposed to a continuous sound pressure level of 94 dB(A) over a period of 1 hour has experienced 1 daily noise dose, that is, the equivalent of a continuous sound pressure level of 85 dB(A) over 8 hours.

What does LC, peak of 140 dB mean

LC, peak of 140 dB(C) means a C-weighted peak sound pressure level of 140 dB(C).  Levels of noise above LC, peak of 140 dB(C) can cause immediate hearing damage. 

This is often referred to as “acoustic trauma” and can result from an event that causes very loud noise, for example, an explosion or metal being machine punched.

How is a person’s hearing damaged

A person’s hearing ability can become temporarily or permanently impaired if the person’s unprotected ear is exposed to excessive noise.

Hazardous Substances

Managing Hazardous Substances in the Workplace

The following issues should be considered when hazardous substances are used in the workplace:

• How hazardous substances should be used;
• How persons are exposed to hazardous substances;
• Whether the risk from the hazardous substance is significant;
• How exposure to hazardous substance in the workplace should be controlled.

Material Safety Data Sheets

Introduction

There are thousands of chemicals in and around the world today.  It is essential to obtain adequate information to avoid any hazard to health in the workplace and the general environment form the use of any chemical.

An ideal way of obtaining practical concise information on a product is through a Material Safety Data Sheet (MSDS).

What Is A Material Safety Data Sheet

A MSDS provides information which allows for the safe handling and use of chemicals or mixtures of chemicals in the workplace.

It describes:

• The identity of the product eg. (formulation or chemical name)
• The properties and uses of the product
• Health hazard information
• Precautions for use
• Safe handling information
• First aid instructions
• Methods for safe disposal

Essentially, the manufacturer of the substance is responsible for the preparation of the material safety data sheet.  In the case of imported chemicals, this responsibility may fall on the importer or local supplier.

The quality of the MSDS may vary from one manufacturer to another.  To overcome this problem, the National Occupational Health and Safety Commission (Worksafe Australia) has produced a booklet called “Guidance Note for Completion of a Material Safety Data Sheet”.

Fire

The potential for a fire to break out on a construction site should never be underestimated.  Even small fires can be costly in terms of damage and delay.

Know What To Do

Remember to follow the site’s fire response procedures, keep your head and above all don’t panic.

You need to be on the lookout for possible fire hazards such as:

• Electrical wiring defects.
• Flammable vapours and dust.
• Accumulated rubbish or flammable liquid spills.
• And hot work activities.

When carrying out hot work, make sure whenever possible that work is carried out in designated areas where no fire risk exists.  There should be no combustible materials close by and check to see that fire-fighting equipment is at hand.

Remember that good housekeeping and the proper disposal of rubbish and waste material is a vital part of any fire safety program.

It is important to use the right type of extinguisher on the material that is burning.

Do not use water or foam extinguisher on an electrical fire – you could electrocute yourself!

If the fire alarm goes off then immediately stop working and evacuate to the assembly area.  Remain at the assembly area until everyone is accounted for and the all clear has been given.

Electricity

Because our bodies are made up mainly of water they make excellent conductors.  Electricity adopts a path of least resistance and you could easily provide that path if you don’t take care. 

Keep an eye out for electrical hazards such as:

• Cracked or faulty insulation
• Equipment that is overheating
• Damp or humid conditions

Always adopt safe work practices when dealing with electricity.  Remove metal wristwatches, jewellery and belts with large metal buckles.  Make sure you wear non-conductive footwear.

Before starting work check to see that your tools are in good shape and clean.  Your electrical equipment should also be thoroughly inspected and tagged by a competent person on a regular basis and records maintained of these inspections.

Remember to keep power cords well away from heat sources, wet areas, sharp objects and other places where they could get damaged.  Run cables at height to keep them dry and prevent them from being damaged.

When working near live power cables, ideally use non-conductive wooden or fibreglass ladders.  Remember to keep as far away from power lines and electrical cables as possible especially in damp conditions.

Residual current devices cut the current if contact is made with any live part.  These devices should be in place and checked on a regular basis.

Avoid Electrical Hazards

• Make sure you are working in a safe environment.
• Don’t wear jewellery or metal wristwatches.
• Check insulation regularly.
• Make sure your tools and equipment are clean.
• Look out for overheating equipment.
• Keep machines well maintained and lubricated.
• Use tools with insulated handgrips.
• Residual current devices to be checked regularly.
• Wear non-conductive footwear.
• Check that a competent person has recently inspected electrical equipment.

Electric Shock Action

• Don’t touch a person if connected to a live circuit
• Call for help and switch off the power.
• If power cannot be switched off then use a non-conductive lever (example a wooden broom) to push or pull victim clear.
• Check for a pulse.
• Place victim in recovery position.
• Cardio-pulmonary resuscitation may be necessary.
• Seek urgent medical attention.

Safety Signs

Sign Layouts

[e.g Australian Standards enter your state/countries] sets out size, shape and colour of the signs in the four categories.

With the exception of Danger signs they are mainly symbolic in their design.

Brief Safety signs draw attention to objects and situations affecting health and safety.

It should be noted that safety signs do not replace the need for proper accident or hazardous prevention measures.

Safety signs are classified into four categories according to their function.  They are:

• Regulatory signs
• Hazard signs
• Emergency information signs
• Fire signs

Purpose, Meaning and Reasons for use

Regulatory Signs

Regulatory signs contain instructions with which failure to comply constitutes either an offence by law, or a breach of standing orders, safety procedures or other workplace directions. 

There are three types of regulatory signs:

• Prohibition signs – Signs that indicate that an action or activity is not permitted
• Mandatory signs – Signs that indicate than an instruction must be carried out
• Limitation or Restriction signs – Signs that place a numerical or other defined limit on an activity or use of a facility

Hazard Signs – Advise of Hazards

There are two types of hazard signs:

• Danger signs – Signs warning of a particular hazard or hazardous condition that is likely to be life-threatening.
• Warning signs – Signs warning of a hazard or hazardous condition that is not likely to be life-threatening.

Emergency Information Signs

Indicate the location of, or directions to, emergency related facilities such as exits, safety equipment or first aid facilities.

Fire Signs

Advise the location of the fire alarms, fire fighting facilities and exits.

Safety Signs and Procedures

Another form of signs used on site are the danger tags or locks and out of service tags.  These tags are designed to prevent another person activating any equipment, valve, electrical supply, switch or tap which may place you in danger.

Danger Tag or Lock out

The personal danger tag should be placed on the main isolating switch, valve, etc. once it has been set to the non-dangerous position.  Be aware that there may be more than one hazard that needs to be isolated.  Make sure you have tagged the correct isolator/switch.

A lockout system may also be used in conjunction with a danger tag.  This enables the workers undertaking work that may place them at risk to attach a lock preventing the isolating switch from being activated. 

Master clips are available that allow a number of workers to each attach their own lock to the isolator switch.  This requires that all workers remove their own lock and danger tag before the switch can be activated.

Remember, the only person who can remove a danger tag or personal lock-out device is the person who placed it.

Out of Service Tag

This tag is used to identify faulty equipment or equipment that is being services.  It should be placed and removed by the same person.  It does not offer any personal protection.  The out of service is primarily used to warn others of hazards.