Timber Kiln Drying Operation Procedure

Purpose. This procedure sets out how kiln charges are built, loaded, dried, checked and unloaded at Heyfield so that timber reaches the target moisture content without degrade and the kilns and heat plant are operated safely.

1.Scope

This procedure applies to the six conventional kilns, the pre-dryer and the biomass heat plant at Heyfield and to all kiln operators, stackers and forklift operators working in the drying area.

2.Building stacks

Stacks must be built on kiln bearers with stickers of the specified thickness aligned vertically at the spacing in the drying schedule for the product group. Boards must be of one species, thickness and moisture group per stack. Stack ends must be flush and the top layer weighted where the schedule requires it.

3.Loading the kiln

Stacks must be loaded on the kiln trolleys with the spacing that allows air flow across every layer, and baffles must be placed to prevent air short-circuiting. The operator must check that the door seals, fans, vents and steam lines are in working order before closing the kiln and starting the schedule.

4.Running the schedule

The operator must load the drying schedule for the charge into the kiln controller, record the charge in the log yard register with the batch identifiers, and check dry bulb, wet bulb and sample board readings at the frequency in the schedule. Any alarm or deviation must be recorded and the coordinator told. Schedules must not be shortened to meet despatch demand.

• Record readings every four hours
• Check sample boards at each schedule step
• Report fan, vent or heat supply faults immediately
• Do not open the kiln during the conditioning stage

5.Checking the charge

At the end of the schedule the operator must test moisture content on the sample boards and on a random selection of boards from the middle and edges of the stacks with a calibrated meter. The charge is released only when the readings fall within the range for the product group. A failed charge must be held, tagged and re-dried or regraded.

6.Heat plant

Only operators holding the boiler operation licence may run the heat plant. Fuel feed, combustion and water treatment checks must be done and recorded each shift, and ash must be handled and stored in line with the site environmental controls.

7.Safety

Kilns are confined and hot spaces. Operators must isolate heat, steam and fans and allow the kiln to cool before entry, and must never enter a kiln alone. Forklift operators must not enter the kiln track area while a trolley is moving.