Identifying low density asbestos fibre board hazards and risks

Identifying LDB hazards and risks

This video presentation provides information on the manufacture and the use of the asbestos containing material known as low density board or more commonly LDB.  The presentation also provides on how to identify LDB, the common locations in which LDB can be found and the associated risk of exposure, should LDB be damaged or disturbed without proper controls being in place.

LDB is a lightly compressed sheet which looks similar to asbestos cement, known as AC sheeting, but it is softer and more pliable. It is also sometimes referred to as asbestos insulation board.

This short film portrays some of the identifiable differences between LDB and AC sheeting. The film was developed for demonstration purposes only in a controlled environment by professionals wearing specific personal protective equipment. It was filmed in a place where persons undertaking renovation construction work failed to identify low density board asbestos containing materials resulting in significant asbestos contamination.

"Okay the difference between these you can actually see there's a patterning on the back of this one and it's very smooth and hard and strong on this side, and there's the weight difference, I can feel it in the way… I don't know, I can't tell but this sheet of compressed Tilux is a lot heavier than the LDB which is in my right hand. And if you flip it over, it's a lot more smoother and you can tell by the edges, the difference and the amount of stuff that's in there. And this is extremely light. Here I can bend and break it by hand, just like that it tears. But this one, I cannot break at all. I am trying but there's no way. I'll break my hand doing it. It's pretty heavy, pretty strong.

LDB was manufactured from the 1950s to the 1970s as both flat and perforated sheets. It is less likely to be found in buildings constructed after 1982. It was used in both commercial and residential applications. It was commonly used as both wall and ceiling linings including external eaves, ceiling tiles and in areas requiring thermal and acoustic insulation, as well as fire protection.

LDB was manufactured and sold under a number of product names. Two of the most common LDB product names are 'Asbestolux' and 'Duralux'.

LDB was manufactured with a range of thickness: 4.5, 6, 9 and 12 millimetres. The edges of the sheets can be a good clue that the material is LDB. Look for bevelled edges which form a V joint, which were very common for LDB and often left uncoloured. Which is in contrast to plasterboard and asbestos cement sheets. Other edge finishes include a square edge where the sheets were commonly installed with a butt joint and finished off with a timber cover strip or a plastic sheet holder. And a completely sealed flush joint which was formed by plastering over the bevelled edge sheets.

Perforated LDB was often used as ceiling tiles for acoustic purposes. Different patterns of perforated ceiling tiles were used with the difference being the number of holes per sheet.

LDB ceiling tiles were manufactured with a pre-painted surface in a range of thicknesses.  The standard ceiling tile dimensions were 1200 millimetres by 600 millimetres.

LDB can contain up to 70 per cent asbestos fibres by volume. Asbestos cement sheeting typically contains between five to 20 per cent asbestos.

The asbestos fibres in LDB are within a soft calcium silicate plaster. The asbestos fibres in AC sheeting are within a hard cement.
Therefore, LDB is softer and more fragile than AC sheeting. LDB will tear leaving ragged or torn edges. AC sheeting will snap and break, leaving sharp edges.

Flat sheet nails and clout head nails will often be embedded or partially embedded or recessed into the surface of the LDB sheeting due to the softness of the sheeting.

In contrast, the heads of the fasteners in asbestos cement sheeting do not sit level with the surface but sit above the surface as shown in the photograph.

Using a flat head screwdriver and light pressure, will leave an indentation on the surface of the LDB sheet as shown in the photograph. If you were to use the same method on AC sheeting, there will be no indentation.

The unpainted rear surface of LDB sheeting can sometimes be viewed in areas such as ceiling spaces. This can often reveal the product name or label.

Here you can see the blue painted AC sheeting has a smoother textured finish in comparison to the yellow painted LDB sheeting. The LDB sheeting would also feel noticeably lighter in comparison than the AC sheet.

Plasterboard products are made from gypsum and have a paper lining. Plasterboard has a more smoother surface than LDB and if you press your thumb nail onto the surface of the plasterboard, it is unlikely that you'll leave a mark.

An assumption that asbestos containing materials is present must be made within all commercial  and domestic buildings constructed or renovated prior to 1990, and within all plant and equipment manufactured or imported prior to 31 December 2003.
If you are unsure if a particular building material or item of plant contains asbestos, always err on the side of caution, and assume that it does.
If you are uncertain as to whether or not a particular building material is asbestos cement or low density board, obtain a sample and have it analysed by a NATA accredited laboratory.

LDB contains a greater volume of asbestos fibres than AC sheeting. Being softer than AC sheeting, LDB will also break more easily. This increases the likelihood of exposure to airborne asbestos fibres when LDB is damaged or removed improperly.

LDB tends to bend and flex when pressure is applied and then will tear rather than snap once it reaches its breaking point. Nails and other fasteners cannot easily be removed from LDB without it tearing and breaking into very small pieces.

LDB is a friable asbestos containing material. Friable means it can be turned to powder form using hand pressure. Its friable nature results in the release of significant amounts of airborne asbestos fibres which could then be breathed into your lungs.
Asbestos fibres in the lungs can result in asbestos diseases such as mesothelioma.

This short film portrays the friability of LDB. It is visually evident that minimal hand pressure is being used to break up the LDB. Note, the visible release of dust and asbestos fibres into the atmosphere. The film was developed for demonstration purposes only, in a controlled environment by professionals wearing specific personal protective equipment. It was filmed in a place where persons undertaking renovation construction work failed to identify low density board asbestos containing materials resulting in significant asbestos contamination.

"I've got a piece of LDB here and what I'll try to do is break it, and I'll crush it. And we can crush it into little pieces, and you can see it breaking up so small, this is why it becomes friable. Look at that. This is only with a gloved hand. I can see it breaking up extremely easily and it can see the stuff emitting into the atmosphere. It's very small. You can see all that fibre in my hand. 

Because LDB is friable, Work Health and Safety and public health law requires that removal must only be conducted by a class A licensed asbestos removalist using friable asbestos removal practices.

This next short film shows the actual removal of LDB. The removal of LDB causes the sheets to buckle and tear releasing large amounts of visible dust and asbestos fibres. This video was provided to WHSQ by a third party. Despite the good use of powered air purifying respirators and an enclosure, there is excessive breakage of the LDB sheets which is not in compliance with the code of practice How to safely remove asbestos. Some workers are also visible not wearing PPE appropriately, including disposable coveralls zipped up not as far as possible. This video is provided only to illustrate how fragile and friable LDB is.

If it's in a good condition and left undisturbed and painted, LDB presents a relatively low risk of releasing asbestos fibres. However, if the LDB is in a poor condition and/or you need to perform regular maintenance and service work, you must engage a class A licensed asbestos removalist to remove the LDB.

Limited maintenance and service work on LDB is permitted if done in accordance with the following work methods approved by Workplace Health and Safety Queensland. Minor repairs, make safe of minor damage to LDB, painting undamaged LDB, drilling holes up to 30millimetres in diameter into LDB, cleaning fixtures attached to LDB, temporarily moving a ceiling tile made of LDB from a metal ceiling grid to gain access to the ceiling cavity. And installing fixtures or fittings into or removing fixtures or fittings into LDB.

Worker training must include the content outlined at the LDB page of the Queensland Government asbestos website.

Training must be repeated at least every five years. Records of training must be readily available and provided to a WHSQ inspector on request.