The volume of poles is calculated; the tank level is then recorded. After treatment the chemicals are returned to the main tank and further measurement is taken. From this we can determine the quantity of chemicals impregnated into the poles as and average for that batch. We can also weigh the poles before and after to confirm the chemical intake.
We then also randomly bore poles to check the depth of impregnation, which should be a minimum of 15mm dependant on sapwood. Should any batches fail to meet the requirements they are put to the side for re-treatment.
After treatment
The poles after treatment are laid out on supports and left for approximately 10 days to let the C.C.A. chemicals fix, or in the case of Creosote to let the excess chemicals drain. The poles are then fixed top and bottom with a wire binding and the ID tags fitted.
RECOMMENDED TREATED WOODPOLE MAINTENANCE
Introduction
Mufindi Woodpoles Plant and Timber Ltd (MWPT) treat and process their wood products to TZS 661:2001 (BS 4072:1999) and TZS 685:2001 (BS 1990:Part 1), but can also treat to other standards or specifications if required. We have a number of inspections and tests in place to ensure that the end product adheres to the client’s requirements and to these specifications. A properly treated Wood Pole for use in the telecommunications and electrical distribution networks can have a life expectancy of over 40 years. There are a number of maintenance practices and rules, which should be followed to ensure the long life of a treated wood pole, both in storage and in the field.
General
A systematic program of pole inspections and maintenance is essential for the following reasons:
- Safety to life and property. – Poles should be maintained above definite minimum strength requirements.
- Efficient service within the system. – Outages or service interruptions due to pole failures should be kept to a minimum.
- Economical operation. – The number of pole replacements should not be excessive and the maximum useful life should be obtained from every pole.
Storage
Treated wood poles should be stored away from continual contact with the ground by wooden supports (old poles or timber). Poles should be stored on level clear ground and away from possible flooding or groundwater at a height of 300mm. They can be layered upwards using similar sizes to conserve on storage area. If poles are to be stored for very long periods the storage area should be covered, chemical leakage should be considered if in close proximity to watercourses or drains.
Maintenance
When a treated wood pole is erected for use in the field, there are a number of destructive forces that can eventually cause a pole ‘failure’. The main ones are decay, insect attacks, fire and lightening. Most utilities have inspection schedules for their wood pole lines and the following should be used as a guideline and not ‘limited to’ for checks and inspections.
Decay:
Wood poles should be checked regularly for any signs of decay. As this is most prevalent at ground level, good practice is to ‘sound’ the poles with a small hammer at the groundline. A ‘duff’ hollow noise can be heard from a pole, which has internal decay.
Remedy: Report and record the suspect pole to the utility supervisor. A further inspection should be carried out to ascertain the extent of the decay and potential life span left within the pole. Depending on the extent of damage the pole should be changed repaired or inspected regularly until changing.
Insect attacks: Insect attacks can usually be seen, and the areas around poles should be inspected for encroaching ants or termites.
Remedy: Clear around the pole area and if necessary treat with environmentally sound insecticide.
Fire: All grasses and twigs etc should be cleared to an area of about 1.8m diameter around pole bases to prevent the possibility of fire damage during dry seasons.
Lightening: If poles are erected in areas prone to lightening, during inspections the full length of the pole should be checked, especially the upper regions where damage could occur from a strike.
NB: The above inspections and preventative measures can increase the life of a treated wooden pole. If during these routine checks any of the above are found, they should be documented on inspection sheets and reported to the utility supervisor. Any further action or investigation can then be carried out as per the supervisor’s instruction.