Dealing with asbestos

Asbestos can be a serious health hazard – are you prepared to deal with it in a safe manner?

As demolitions ramp up in Christchurch and Auckland, there will be plenty of situations where you encounter asbestos. It is the contractor’s responsibility to check for asbestos and have a plan in place to deal with it.

Health risks from asbestos

Asbestos is a health hazard if it is friable – easily crumbled – as airborne fibres can be inhaled and become embedded in the lungs. The inflammation and subsequent scarring of the lung tissue by the asbestos fibres can result in diseases such as asbestosis, lung cancer and mesothelioma. It may take more than 20 years before an asbestos-related disease develops.

Undamaged, non-friable asbestos presents little risk to health. However, when it is damaged as a result of age, weathering, abrasion, waterblasting, chemical or algal attack, or the effects of fire, it is likely to become friable.

Who is at risk?

Asbestos-containing building materials are likely to have been damaged in the earthquakes and will certainly be damaged during demolition. This means that demolition and construction workers are at significant risk of exposure.

Specialist asbestos removal contractors must hold a certificate of competence that demonstrates they have the knowledge, skills and experience to remove asbestos safely. Most regular contractors are unlikely to have the appropriate knowledge for this task.

Who is responsible for safety?

Although the Health and Safety in Employment Act 1992 places the responsibility for the safety of employees with the employer, demolition and construction workers must be aware of the dangers of asbestos and know how to manage any risk to themselves and to others.

Conduct a survey to help determine the level of risk

Before a contractor begins work on a house, they should carry out a simple survey to satisfy themselves they are not at risk of exposure to asbestos. Some questions need asking.

1) How old is the house?

The first indicator as to whether asbestos is likely to be present or not is the age of the house. Asbestos and asbestos-containing materials (ACMs) were very widely used in the building industry from the late 1930s until around 1990.

2) what materials have been used?

Many materials in buildings built or renovated during this period are likely to contain asbestos (see Figure 1). External materials containing asbestos may include corrugated Super Six roofing, guttering, downpipes and rainwater heads, asbestos-cement soffit linings, external wall claddings such as asbestos-cement sheets and shingles, imitation brick and stone claddings and stucco plaster over asbestos-cement sheet.

Interior finishes and materials may include stippled and textured ceilings, suspended ceiling tiles, the backing to vinyl and linoleum sheet and tile flooring, the lining board behind a gas heater or a fuse board, hot water pipe and cylinder lagging, and insulation.

Flues, metal flue joint and wood burner seals and night-store heaters may all contain asbestos. Asbestos was also sometimes added to plasterboard and plasterboard jointing compound, and lathe and plaster skim coats have been found to contain asbestos.

A more detailed survey may be needed

If the answer is ‘no’ to both these questions – ‘Was the building built or renovated between 1940  and 1990?’ and ‘Is there any other evidence of asbestos?’ – then no further assessment is required and repair or demolition work can begin. If the answer is ‘yes’ to either question, a more detailed survey should be carried out.

How to carry out a more detailed survey

A more detailed survey should include:

• Drawing a simple floor plan.
• Identifying all rooms and spaces on the plan.
• Working through a checklist to identify locations in the house where there may be asbestos.
• Recording all locations where asbestos might be present on the floor plan.
• Be systematic when carrying out the building survey and document all results on the checklist (see Table 1).

Take a sample for testing

The only way to know for sure whether a material contains asbestos is to have samples tested at an IANZ-accredited laboratory. Samples must be taken by a person competent to work in asbestos-hazard conditions, without risk to their own or others’ health and safety. They should know:

• The types and applications of ACMs.
• The correct use, maintenance and storage of personal protective equipment (PPE).
• The hazards of asbestos exposure.
• The safe use of plant and equipment to be used.

When taking samples, it’s important to:

• Be methodical.
• Take several samples in each location.
• Identify and record the location of each sample.
• Store samples from different locations separately.

By carrying out a survey and treating any suspected material as if it contains asbestos, the contractor minimises any exposure risk to themselves and to others.

Checklist for identifying potential locations of asbestos

Location	Check	Yes	No
Ceiling	Are ceilings stippled/ textured
	Are there suspended ceiling tiles?
Interior linings	Are walls sprayed/ textured?
Flooring	Is flooring vinyl sheet or tiles?
Insulation	Is there insulation in the walls or ceiling that may contain absestos?
	Does the wood burner or flue have seals that may be asbestos?
	Is there a gas heater with suspected asbestos-containing lining board behind?
Fuse/ meter board	Is there a fuse board with suspected asbestos-containing lining board behind?
	Is the roofing corrugated asbestos-cement?
	Do gutters/downpipes/rainwater heads appear to be asbestos-based?
Soffits exterior cladding	Are the soffits a sheet cement-fibre board material?
	Is the cladding a sheet or shingle cement board?
	Is the cladding imitation brick/stone?
	Is the cladding stucco over asbestos-cement sheet?

Key points for abestos

• If you think asbestos is present, act as if it is.
• Do not assume that a material does not contain asbestos.
• If asbestos is found in one part of a building, it is likely to be in similar materials in other parts of the building.