Columnists Features

ZABS revises standard on sawn timber

ZABS CORNER with LEE HAAMUNJI
JAMES Chipwanga has been a tenant for a decade now. He feels bad every time he pays rentals. To him, rentals are somewhat modern-day slavery because you do not have peace of the mind as you live in a rented house at the mercy of the landlord.
Mr Chipwanga has given himself five years in which to own a house and become a landlord as well.
In this column, I will share with our dear readers and people like Mr Chipwanga the measures that ZABS has put in place to ensure that those planning to build houses have materials that meet the required standard.
The construction industry plays an integral role in the development of any economy.
In Zambia, the sector has been recording steady growth, mainly due to construction of houses, investments in the mines, road construction and other civil works.
ZABS, through the sawn timber technical committee (TC 8/1), is in charge of preparing Zambian standards for sawn timber.
The following standards are currently being revised to ensure that the safety and quality requirements of sawn timber are consistent with the changing needs and technology advancements:
1. DZS 440 Sawn Timber – Terminology
2. DZS 441 Sawn Timber – Indigenous Hardwoods Part 1: Furniture Timber Specification
3. DZS 444 Sawn Timber – Measurement of Features – Code of Practice
Sawn timber is timber that is cut from logs into different shapes and sizes. It is generally cut into varying rectangular widths and lengths, but may also be wedge -shaped. Common sawn timber products include solid timber beams and more rectangular timber sections.
Sawn timber can be used for general building works; in gardens for construction, raised beds, path edging, fencing and many more.
One of the ways to improve the quality of sawn timber is by grading the wood. This is done to establish and maintain acceptable standards of evaluation irrespective of the source of wood, so that a given grade will set a standard that can be used as a basis on which to contract.
To do this, a specification is required which supplies information concerning the grades of wood of indigenous trees suitable for the manufacture of furniture, thus, the importance of having a Zambian standard with such specifications. This in turn helps demonstrate the manufacturer’s competency in the markets both locally and abroad.
Another way to improve the quality of sawn timber is to have the moisture content measured. It will be in the interest of a furniture manufacturer to acquire the necessary instruments to measure moisture content to prevent warping.
Care should be taken during the seasoning process to prevent the development of seasoning stresses and a high moisture gradient in the seasoned timber.
The sapwood of most hardwood timber is subject to attack by the larvae of various species of beetle during the period when timber is being air-seasoned after sawing and also during storage; both the sapwood of maculate (eucalyptus maculate) and that of kiaat (pterocarpus angolensis) are, for instance, particularly liable to attack.
To protect the sapwood of hardwoods during air-seasoning and subsequent storage, the freshly sawn boards should be immersed in (or to roughly sprayed with) a suitable insecticide. Timber treated in this way should be block-stacked for about 48 hours before open-stacked in the seasoning stacks.
This treatment serves only to arrest attack up to the time of manufacture and cannot be regarded as a permanent preservative treatment.  However, if the wood is free from all stages of beetle infestation at the time of manufacture, it is unlikely that it will be infected later.
Zambia is an exporter of sawn timber, and to help stakeholders demonstrate their competency in the markets locally and abroad in terms of quality and safety, it is imperative that new technology advancements and better codes of practices are employed in the Zambian standards.
Manufacturers should also aim at making use of Zambian standards not only to increase their profit share but to also meet international set standards and provide safe and quality products to their consumers.
People like Mr Chipwanga who are building houses can come to ZABS and buy the standard on sawn timber so that they are more enlightened.
The author is Zambia Bureau of Standards public relations officer
For more information contact;
The Director
Zambia Bureau of Standards Lechwe House
Freedom Way – Southend P.O. Box 50259,
Lusaka,-Zambia
Tel: +260-211 231385
Email: lee@zabs.org.zm
Website: www.zabs.org.zm

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