About me: I have considerable qualifications in H&S culminating in a NEBOSH Diploma level 6, I taught the CSCS card to students entering industry, taught IOSH Managing Safety to external bodies, I was the UCU (University College Union) H&S representative, and was an integral part of the H&S Committee. I was the IOSH nominated person to represent Knowsley Community College, and taught NEBOSH General courses. I have since left education and returned to site three years ago. I have taught Brickwork and Multi Skills courses up to level three and I am qualified and experienced bricklayer, assessor, internal verifier and lecturer. I have experience working in a very large college, a selective college, small private training centres, and in privately run schools over twenty years.
The problem: Respirable crystalline silica (RCS) is a dust that is invisible to the human eye unless large amounts are generated such as when cutting flagstones or brick with a circular saw when a cloud of dust that appears like smoke is there, then disappears when blown away by the wind. A human hair is 70 microns thick, the human eye can see up to 35 microns, RCS typically is between 5 microns and 0.2 microns. Figures suggest that RCS kills 15 people per week from work exposure. RCS is a substance that is a carcinogen, and like asbestos takes many years to manifest (long latency period) itself and also like asbestos once you have the disease your life expectancy is significantly reduced and your lifestyle is significantly affected. You cannot see it, and you will not feel the effects at the point of exposure, however that doesn't mean it is not harming your health. Exposure has to be reduced. IOSH have a campaign called 'No Time to Lose', to immediately tackle carcinogens in the workplace of which RCS is a leading topic.
The facts: The risk of being exposed to RCS is real and being highlighted in all industry courses and qualifications, and control measures that are being applied and stringently managed by industry. However, as colleges are somewhat distanced from industry and managed by non-occupational personnel the dangers of RCS may go unnoticed, it was often expressed as 'it's dusty in here isn't it?' or ‘you would expect dust in the construction industry!’
The problem: Mortar contains RCS and is the medium used in colleges to bind bricks together just like sand and cement. It is used as it sets hard enough to build with but can be re-used as it is not permanent. Students build walls which can take up to four to six weeks to complete so therefore the mortar quickly becomes dry. As colleges need to re-use the bricks and mortar, they are cleaned off by hand often by the students whenever they have finished. This generates large amounts of RCS dust, which exposes everyone in the workshop. The mortar is then moved to the mortar mill, this is where the mortar is crushed back down to remove any lumps so it can be reused. Once again the loading of the dried mortar into the mill produces significant levels of RCS dust, which is only stopped once it enters the mortar mill as it is then mixed with water to mix up (water suppressing). Add to the fact that mortar used in colleges contains lime as the setting agent which is corrosive. Lime in the powder form burns when it becomes wet, when the lime mortar dust enters the nose or the eyes the body produces water in the form of a runny nose or tears to remove the dust. This activates the corrosive nature of the dust, burning the nasal passages and affecting the mucus membrane.
Often managers open windows or doors to ventilate the dust, this is not the solution! Producing an airflow will 'whip up' any dried RCS dust on the floor or high beams and lights and once again put them into the breathing zone. The size of the dust means it is light enough for it to suspend in the air for long periods.
Legal: RCS has been given the lowest work exposure Level (WEL) by the HSE of 0.1 mg/m3 over an eight hour period. Cutting a paving stone can produce 700mg/m3 in a matter of seconds.
Can we manage it better? We cannot totally eradicate exposure, we can however put in place systems that drastically reduce exposure. As of yet there are no credible alternatives to mortar so we cannot eliminate it or substitute it. We can provide LEV (Local Exhaust Ventilation) to suck the dust out of the area however this can put the dust into the breathing zone as it rises to the LEV. We can prevent exposure to students by providing a safe system of work (SSW) where the work is taken down after they have left the workshop by technicians, limiting student exposure. All work being taken down could be wetted down and the floor area kept wet, a portable LEV could be set up over the area to be worked on and the technician fitted with an appropriate RPE, with face fitting, clean shave and under the management of Occupational Health. Ban brushes as they lift the RCS dust into the air, purchase industrial vacuum sweepers fitted with hepa filters and ensure a regime of emptying regularly and safely. At the area of recycling, all recycled mortar that is dropped could be dropped in a place with a fine water sprinkler in situ to suppress any remaining dust and to keep the mortar damp. The mortar mill could be kept in an area that is separate to the workshop to further prevent unnecessary exposure. As you will probably have realised the key control measure is to suppress the dust by keeping it wet. These requirements are standard in industry however in my many years of experience these standards applied against RCS in colleges are not wholly apparent.
I do hope you find my piece informative and it helps in anyway getting the message across. If I can be of any further assistance or give any further information or advice please don't hesitate to ask. As a person who has over forty year’s experience in both the education and construction sectors, coupled with my experience and knowledge of H&S it is something that should be listened to. As the IOSH campaign says 'No time to lose', we need to act now not to frighten or deter people from participating in the construction sector, but to protect them and give them a long working life. Finally I mentioned earlier the dust generated by the circular saw, how many times have you seen workmen cutting flagstones on the pavements and you see that large plume of dust? Maybe now you may have the knowledge to avoid that dust cloud it is a killer a hidden killer!
Keith Rowson, Grad IOSH