The vertical panel saw $($VPS$)$

KH offers a woodcutting service. Customers purchase the wood in store and have it cut, or they can bring in their own wood to be cut. This is carried out using a VPS that has been in use since the store opened. The VPS is located at the back of the store, between the two sets of automatic sliding doors for the outside areas, that are constantly opening and closing.

The task of carrying out the cutting is not allocated to one individual worker. Instead, there are five workers who are trained on how to operate the VPS safely. Depending on which of the workers are available each day, they decide between themselves who will do the cutting on that day. Whenever Worker X is working, they always volunteer to take on this role and the SM is happy with this arrangement. Worker X then takes on tasks in the area close to the VPS$,$ this way they are nearby when a customer wants to use the cutting service. Worker Y also likes to work on the cutting service, but the SM has noticed that Worker Y is often breathless and coughs a lot while working on the VPS$.$ The SM is conscious that the customers do not want to be near someone who is coughing, while waiting for their wood cutting to be done.

Recently, Worker X has noticed that there has been a steady increase in the demand for the wood cutting service in general, but the weekends are the busiest days. Some days, Worker X spends several hours working on the VPS$.$ A pair of earmuffs $($ear defenders$)$ and eye protection are available for use by the workers. Most workers do not use the old and dirty earmuffs. The VPS originally had an on$-$tool extraction system but, some time ago, workers complained that this made the blade difficult to position accurately, so it was removed. Dust tends to build up along the length of

the VPS and on the floor around it$.$ Workers use a broom to sweep the wood dust into a pile around the back of the VPS at the end of each day. This pile of dust is vacuumed up every few days.Supporting document $4$

Extracts from Occupational Hygienist$$s Report.Part $1$ Exposure of worker to wood dust

Introduction

Keystone Hardware requested monitoring of wood dust exposure to be carried out for one worker operating the vertical panel saw $($VPS$)$ during a typical working day.

Monitoring strategy

The sampling strategy was in line with a Basic Survey as described in the HSE document HSG$173$ and intended to look at a worst$-$case situation.

Sampling Method

Personal exposure to wood dust was monitored using the HSE Method for Determination of Hazardous Substances $($MDHS$)14/4.$ This method uses gravimetric analysis and can be used to determine the inhalable fraction.

The inhalable fraction is an approximate amount of airborne material that enters the nose and mouth during breathing and is therefore available for deposition anywhere in the respiratory tract.

In this situation, the airborne material is a mixture of hardwood and softwood dust generated as the worker operates a VPS$,$ cutting a range of wood for customers.

Further detail of the equipment and method used is given in MDHS $14/4.$

Results

The data in Table $1$ overleaf shows the results from personal dust sampling carried out for Worker X during one working day.

Table $1$

Working period Wood cutting task Exposure mg$/$m$3$

$08$:$0009$:$00$ Oak fire door $2\mathrm{.}9$

$09$:$3010$:$15$ Oak floorboards $3\mathrm{.}8$

$10$:$4511$:$15$ Pine floorboards $6\mathrm{.}0$

$13$:$3015$:$30$ Plywood sheets and mahogany stair rails $4\mathrm{.}6$

$15$:$4516$:$45$ Chipboard sheets $5\mathrm{.}0$

$17$:$0017$:$45$ Pine floorboards $4\mathrm{.}6$

At all other times Worker X is carrying out other work tasks and therefore their exposure to wood dust is assumed to be zero.

Part $1$ Recommendations

The information gathered during this basic survey, and the resultant $8-$hour time weighted average $($TWA$)$ personal exposure calculated, have indicated that there is a need to take action.

Three areas of action are recommended:

$1\mathrm{.}1$To carry out a detailed survey in line with HSG$173$ appendix $2.$

$1\mathrm{.}2$To take steps to improve the control measures in place, especially where existing control measures have not been maintained

$1\mathrm{.}3$Establish a health surveillance programme for those workers operating the VPS$.$

In relation to Part $1$ recommendations above, it will be necessary to carry out a much wider programme of monitoring to collect representative samples and not just samples that relate to a worst$-$case scenario.$($v$)$ The OH made some recommendations in their report $($see supporting document $4).$ One of these recommendations was to carry out a detailed survey of workers$$ exposure to wood dust.

What should the OH consider when designing this detailed survey?