1.2 Manufacture
Large batches of pulverised fuel ash (pfa) a recycled product from
modern coal burning power stations and/or finely ground sand are mixed
with cement and/or lime in a slurry to which a small quantity of aluminium
powder is added. The slurry is discharged to part fill large steel
moulds. The aluminium powder reacts with the alkaline environment
of the mix to generate tiny bubbles which stabilise to form the Aircrete
cellular structure.
The slurry rises to fill the moulds and sets to a firm but relatively
soft consistency suitable for cutting into block size pieces with
tensioned wires on cutting frames.
Curing in giant autoclaves by steam at some ten times atmospheric
pressure chemically converts the raw materials into a highly stable
and durable structure which completes the manufacturing process. When
the blocks are removed from
the autoclaves they are ready for use as soon as they have cooled.
Aircrete is produced under quality control systems to BS EN ISO 9001
at all stages of the production and delivery process in large factories
with in-house laboratory facilities which are independently assessed.
The energy input of autoclaving is offset by the use in the manufacturing
process of recycled materials such as pfa and by energy savings in
use due to the thermal insulation the products provide. Waste material
produced during manufacture is recycled in the manufacturing process.
Energy used in transport to site is less than that for heavier masonry
materials as a greater volume of material is delivered for a given
transport weight.
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1.3 Environmental policies
Aircrete manufacturers are committed to a responsibility to the environment
as embodied in their environmental policies. They constantly assess
and seek to improve environmental performance whenever it is reasonably
economic and
practical to do so and operate Environmental Management Systems to
BS EN ISO 14001.
Annual improvement targets are set on waste minimisation and energy
efficiency.
In developing their business, products and services, Aircrete manufacturers
undertake to pay particular attention to the following measures:
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Comply promptly with all applicable laws and regulations concerning the environment |
• |
Develop operational procedures and manufacturing processes to minimise, as far as it is reasonably practicable, pollution risks to the environment |
• |
Take positive action to reduce the waste generated by their activities and encourage energy conservation, recycling and re-use, wherever practicable |
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Provide the necessary training and support to employees to enable them to maximise their contribution towards protection of the environment |
• |
Encourage suppliers, contractors and customers to share in their aims to promote excellence in environmental management |
• |
Consider the expectations of all interested parties. |
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