You may have heard the phrases Class A, Class B or friable floating around when discussing asbestos. But what do these terms actually mean? You may be in the process of looking into asbestos removal, or simply needing some clarification. 


A brief history on asbestos


Until the 1980’s, asbestos was commonly used in building materials. It was a cheap, long lasting and fire retardant material. Used in spray-on fireproofing, insulation, cement, roofing sheets and insulation around pipes. Eventually, the health hazards from being exposed to asbestos fibres were discovered and as a result the product is no longer used. But if you live in a house that was built or renovated between 1950 - 2000, it’s possible there could still be asbestos, or asbestos containing material (ACM) in the building materials. 


The 2016 asbestos regulations have been enforced as of April 2018. These state that if you own or occupy an asbestos containing building you need a management plan. You must also have your home checked for asbestos if you plan to renovate or demolish any parts of your home. As soon as you start renovation plans, you become a PCBU (Person Conducting Business or Undertaking) and you are therefore responsible for anyone coming on to your property.


If there are no traces of asbestos, this needs to be documented. If there is asbestos material present, a plan for the asbestos management needs to be put in place and regularly updated for anyone who will be working on or in the property. 


Why not remove all asbestos when you know it is present?

Not all asbestos can be immediately threatening, so don’t panic. Asbestos containing materials (ACM) can be left intact if they are in good condition or well painted and undisturbed. It is often best to leave asbestos in good condition alone, to prevent contamination. However, the management plan needs to have procedures set in place in the event that the asbestos becomes exposed and airborne. 

Learn more about managing asbestos in your rental property with our free downloadable guide 

Class A Asbestos: 

Class A asbestos is known as ‘friable asbestos’. The name is given to asbestos materials that are powdery or can become dust from being crushed when dry. This is considered the most dangerous class of asbestos and requires a Class A license to remove. With little pressure from your hand it can become dust and release asbestos fibres into the air. This poses the biggest threat as it can easily come in contact with skin or be inhaled by anyone in the area. The asbestos percentage in friable asbestos can be as high as 100% pure asbestos.



Friable asbestos products are commonly found in: 

  • Floor tile backing

  • Thermal insulation

  • Sprayed coatings

  • Deteriorated Class B asbestos

  • Asbestos contaminated dust (ACD) which could be produced from Class B products



Any work involving Class A asbestos are always conducted under full containment, with certified air filtration devices and sealed air locks. A licensed removal company like Chemcare will have Personal Protective Equipment (PPE) and full coverage masks certified for any asbestos removal job. This is most important with class A asbestos as it is more likely to have airborne fibres during removal. 


Removal specialists may use a wet removal method, wetting the area with specialised dust suppressants to reduce airborne asbestos fibres. You must have a licensed assessor on site to monitor air levels and determine when it has been cleared of asbestos or is completely safe. 



Class B Asbestos: 

Class B asbestos is considered ‘non-friable’ as it is bonded asbestos, normally mixed and sealed into products. Compounds like cement or plastic can be mixed with asbestos (with usually less than 15% asbestos) to create a stronger product. It is bound tightly and cannot be easily crumbled to expose asbestos fibres. Bonded asbestos is considered safe if it is maintained - there is low risk if it is not disturbed.


Class B asbestos can be found in:

- Vinyl composite tiles (VCT)

- Cement products such as: cement sheet, pipes and

gutters & roofing

- Electrical resin products

-Bituminous products



A removal specialist will need a Class B license to remove non-friable asbestos. Class A licensed companies can also remove Class B but must have Class B trained and certified supervisors.  As there is less chance of airborne fibres, there is lower risk. Tradies or building site managers will often get this licence so they can deal with any small amount of asbestos they come across during day-to-day work. 


Asbestos Deterioration

Damage and deterioration will increase the risk of Class B material becoming friable. You need to be weary of changes or physical impact if chosen to leave the asbestos. 

Class B asbestos will break down faster with:

  • Water damage

  • Cutting

  • Drilling

  • Impact

  • Continuous vibration/earthquakes

  • Age


Asbestos Management plans need to be updated every 5 years to note any changes as per the new regulations. 


Cleaning procedure

Ministry of Health NZ has information and courses to learn how to remove asbestos from homes. However, even with this information, DIY asbestos removal can be risky, and involves all the right equipment and proper disposal. You can expect a proper asbestos removal to involve:

  • Sealing the area with layers of plastic.

  • Covering electric units, air ventilation systems and removing furniture.

  • Setting up an air pump asbestos monitor (to monitor the amount of fibres in the air).

  • Removal specialists being equipped with high quality respirators and suits. These will also need to be disposed of properly afterwards.

  • Wetting areas that could release fibres into the air, removing asbestos with non-abrasive machines to reduce dust.

  • Using a H13 DOP Certified vacuum to remove the small particles.

  • Removing and disposing of asbestos material at approved council dumping sites.

  • Monitoring and testing levels post clean (clearance testing).



How do I know if it is Class A or Class B asbetsos?

Don’t go ahead and start ripping up your floorboards if you think there might be only class B asbestos underneath. Asbestos is invisible, there is no physical confirmation that it's present. You won’t be able to tell if it is Class A or B present without a thorough asbestos sample survey. Definitely get a professional in to survey your home and then discuss options for an asbestos management plan.


Asbestos lurks in most Kiwi homes, as it's rare for surveyors to inspect a home without some asbestos material. Class A, friable asbestos needs to be dealt with straight away by licensed professionals. Class B most often can be removed or covered for your peace of mind, or left and monitored through regular inspection. If you suspect your home has some kind of asbestos inside, contact a professional before you begin any renovations or DIY investigation yourself.


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