GB/T 4669-2008Textiles -- Woven fabrics -- Determination of mass per unit length and mass per unit area (English PDF)

3.1 Method 1 and 3

For the whole section or a piece of fabric whose humidity can be implemented in standard

atmosphere, then, after humidifying, determine the length and mass of the fabric; calculate

the humidifying mass per unit length. Or measure the length, breadth, and mass of the

fabric; and calculate humidifying mass per unit area.

3.2 Method 2 and 4

If the whole section of fabric cannot be humidified in standard atmosphere, then, after

loosing it in average atmosphere, measure the length (breadth) and mass of the fabric;

calculate the mass per unit length (area); then correct them with correction factor. The

correction factor is decided by cutting a part of the loosen fabric; measure it in the average

atmosphere; and measure again in standard atmosphere after humidifying; compare the

length (breadth) and mass of the two results.

3.3 Method 5 (humidifying mass per unit area of small fabric)

For small fabric, place it in standard atmosphere and humidify first; cut samples and weigh

it as per the stipulated size; calculate the humidifying mass per unit area.

3.4 Method 6 (Dry-out mass and conditioned mass per unit area of small fabric)

For small fabric, cut samples as per the stipulated size; put it into drying oven to dry-out

and weigh until the mass is stable; calculate the dry-out mass per unit area. Calculate the

conditioned mass per unit area by combining with the conditioned moisture regain ratio.

4.1 Steel ruler

The division value is cm and mm. Length of 2 m ~ 3 m is used for Method 1, 2, 3, and 4.

Length of 0.5 m is used for method 5 and 6.

4.2 Scissors

It can be used to cut the fabric to the stipulated size.

4.3 Balance

It can accurately measure mass of a whole section or a piece of fabric; the accuracy is ±2%

the mass of the measured samples. The accuracy of Method 5 is 0.001g, and the accuracy

of Method 6 is 0.01g.

4.4 Workbench

The surface is smooth and flat, the width is bigger than the breadth of the measured fabric,

and the length meets the measuring requirement.

4.5 Cutter

The accuracy is ±1%, and it can cut 10 cm × 10 cm square samples or round samples with

Cut five representative samples from non-edge and non-wrinkle parts of the fabric (or as

per other stipulations); each sample is about the size 15 cm × 15 cm. If local areas are of

obvious different masses per unit area because of large pattern, select integral multiple of

samples of complete design of this pattern.

6.7.2 Procedures

Pre-humidify samples according to 6.1. Place the samples in standard atmosphere with no

tension for humidifying for at least 24 hours to reach balance. Arrange each sample on the

workbench (4.4) in sequence. In proper area, use a cutter (4.5) to cut square samples of

10cm ×10cm and round samples of 100 cm2; it is also allowed to cut integral multiple

rectangle samples of complete design containing large pattern which meets requirements

in 6.7.1; and measure the length and width of the samples.

Weigh the samples to the accuracy of 0.001g. Make sure that the yarns of the samples are

not lost during the weighing.

6.8 Method 6. Determination of dry-out mass and conditioned mass per unit area of

small fabric.

6.8.1 Samples

Cut samples according to 6.7.1.

6.8.2 Procedures

6.8.2.1 Cut samples

Arrange each sample on the workbench (4.4) in sequence. In proper area, use a cutter

(4.5) to cut square samples of 10cm ×10cm and round samples of 100 cm2; it is also

allowed to cut integral multiple rectangle samples of complete design containing large

pattern which meets requirements in 6.7.1; and measure the length and width of the

samples.

6.8.2.2 Dry out

6.8.3.3.2 Inner box weighing

Put all the samples into the weighing vessel (4.7) of the ventilated type dry oven (4.6); dry

them to stable mass at the temperature of 105°C ± 3°C (weigh the samples at intervals of

at least 20 min until when the difference between two weights does not exceed 0.20% of

the latter mass).

6.8.2.2.2 Outer box weighing

Put all the samples into the weighing vessel (4.7); then put them all in the ventilated type

dry oven (4.6); open the vessel cover; dry them to stable mass at the temperature of 105°C

The results shall be rounded to single digits as per stipulations in GB/T 8170.