Candidate Support Pack - Scottish Qualifications Authority

The classification of domestic and personal soiled fabric items involves a greater
awareness of fabric types. You must be aware of what each item is made of and how this
fabric will respond to the wash process your classification will give it.
The added difficulty with domestic and personal items is that they are often made up of
mixed fibres and are not of a standard quality.
You will be expected to use your skill gained from training and experience to assess items
for their washability as you count and mark them.
Polyester has taken over from natural fibres as the most common fibre in use today.
Polyester was first patented in 1941, and since then there have been many types
developed from different base chemicals.
Polyesters are very hard wearing and can withstand misuse. But they can be cold next to
the skin and are not suitable for all applications. For example, sparks from welding would
make a polyester overall melt and polyester sheets are uncomfortable to lie on for long
periods. They are resistant to acids and all types of bleaches, but can be damaged by
very strong alkalis.
Polyester, however, has several major drawbacks. It attracts oily and fatty soiling, tends to
generate static electricity when agitated and forms creases that detract from the laundered
finish.
A polyester fibre is a type of plastic, and when it is heated in the laundry process it can be
bent, which causes a crease in the fabric. There are two main reasons for these creases:
• Thermal ‘shock’ creasing is caused when the hot pliable polyester fibres are cooled
down quickly, setting the fibres in a bent and twisted state. To overcome this problem
the wash and drying process has to include a cool down period where the
temperature is slowly reduced to about 52 °C slowly (at approx 4 °C per minute).
• Pressure creasing can be caused by the weight of the work during the hot wash in a
large capacity machine and by over-extraction or extraction when items are still hot.
Any polyester items left in barrows or cages after washing will develop creasing.
To try to gain the benefits of both types of fibres, many items are manufactured from a
mixture of cotton and polyester. It should be noted that the cotton in these polycotton
items would be damaged if hypochlorite bleach were used.
Activity 16
List the natural fibres used to make up fabrics washed in your laundry.
Answer sheets p. 3.47
GC8N 22 — Laundry Operations Level 2 3.27