Controlling silica exposure during fettling of castings

In foundries, once  the casting is removed from the mould it is usually necessary to remove excess metal and remedy defects. This process is usually referred to as “fettling” or “finishing”. Fettling normally involves the use of powered hand tools such as chippers and grinders. The operation presents a number of significant risks. Using power

What’s a thorough examination and test?

Companies that have installed local exhaust ventilation systems have to undertake a “thorough examination and test” (TExT) at least once every 14 months. The objective of the TExT is to find any significant defects and to have them remedied to regain control. In most cases they will employ an external organisation to carry out these

Controlling solder fume

In a previous post I discussed the health risks associated with exposure to the fume generated during soldering with rosin cored solder. It’s a respiratory sensitiser, and is one of the main causes of occupational asthma in Great Britain. The fume is generated due to thermal degradation of the flux – usually containing colophony (also

Designing and managing local exhaust ventilation

Local exhaust ventilation (LEV) is one of the main measures used to control worker exposure to hazardous substances. It’s difficult to work out exactly how many systems there are in Britain, but the Health and Safety Executive carried out some research in 2006 and estimated that there were between 260,000 and 330,000 businesses that have

To test or not to test?

I recently received the following query from a client: “I have come across various items of equipment which appear to have integral LEV types of arrangement ……..  All have been introduced to reduce the level of dust or chemical that may have a deleterious effect on the user of the equipment.  I am unsure if

Testing walk-in spray booths

We recently received a query from a client who carry out paint spraying of isocyanate based two pack paints in a large walk-in type spray booth. They wanted us to carry out sampling to help them to decide when it was safe to enter the booth without their workers wearing their air fed masks. This

Glove boxes

Glove boxes are often used in the pharmaceutical industry to control highly toxic “active” agents used in drug formulations. In principle they should provide a high degree of protection for the user. The contaminant is completely contained inside an extracted enclosure while the worker is outside. So when we’re carrying out a risk assessment and

What is “static pressure”?

We were running the BOHS module course P601 “Commissioning and Thorough Examination and Testing of Local Exhaust Ventilation Systems” last week. One of the concepts delegates often find difficult to get to grips with is “static pressure”, which is one of the main engineering measurements carried out during the testing of a local exhaust ventilation

Visualising Airflow

It can be difficult to make a qualitative evaluation of the effectiveness of LEV hoods because the contaminants are either invisible (in the case of most gases and vapours) or difficult to see (with fine dusts). Two main techniques can be used to overcome this problem: smoke tests dust lamps Smoke released in the vicinity

What’s wrong with captor hoods?

Captor hoods are one of the most common types of inlet that you’ll find on extraction systems. With these hoods, the contaminant is generated and disperses outside the hood. It has to be drawn into the system by the airflow. Unfortunately, in most cases, they are largely ineffective at controlling contaminants. The following diagram illustrates