The Measuring Instruments (Non-Prescribed Instruments) Regulations 2006

Part F Dimensional Measuring Instruments

54.  The relevant essential requirements of Part 1 and the specific requirements of this Part apply to dimensional measuring instruments.

Requirements common to all dimensional measuring instruments

55.—(1) Electromagnetic immunity

(2) The effect of an electromagnetic disturbance on a dimensional measuring instrument shall be such that—

(a) the change in measurement result is no greater than the critical change value as defined in paragraph (3); or

(b) it is impossible to perform any measurement; or

(c) there are momentary variations in the measurement result that cannot be interpreted, memorised or transmitted as a measuring result; or

(d) there are variations in the measurement result severe enough to be noticed by all those interested in the measurement result.

(3) The critical change value is equal to one scale interval.

Length measuring instruments

56.—(1) Characteristics of the product to be measured

(a) Textiles are characterised by the characteristic factor K. This factor takes the stretchability and force per unit area of the product measured into account and is defined by the following formula—

K = ε(G + 2.2 N/m²), where—

(i) ε is the relative elongation of a cloth specimen 1 m wide at a tensile force of 10 N;

(ii) G is the weight force per unit area of a cloth specimen in N/m².

(2) Operating conditions

(a) Range:

Dimensions and K-factor, where applicable, within the range specified by the manufacturer for the instrument. The ranges of K-factor are given in Table 21—

Table 21

Group	Range of K	Product
I	0 < K < 2 × 10-2 N/m2	low stretchability
II	2 x10-2 N/m2 < K < 8 × 10-2 N/m2	medium stretchability
III	8 x10-2 N/m 2 < K< 24 × 10-2 N/m2	high stretchability
IV	24 × 10-2 N/m2 < K	very high stretchability

(b) Where the measured object is not transported by the measuring instrument, its speed must be within the range specified by the manufacturer for the instrument.

(c) If the measurement result depends on the thickness, the surface condition and the kind of delivery (e.g. from a big roll or from a pile), corresponding limitations are specified by the manufacturer.

(3) MPE

(a) Instrument

Table 22

Accuracy class	MPE
I	0.125 %, but not less than 0.005 Lm
II	0.25 %, but not less than 0.01 Lm
III	0.5 %, but not less than 0.02 Lm

• where L_m is the minimum measurable length, that is to say the smallest length specified by the manufacturer for which the instrument is intended to be used.

(b) The true length value of the different types of materials should be measured using suitable instruments (e.g. tapes of length). Thereby, the material which is going to be measured should be laid out on a suitable underlay (e.g. a suitable table) straight and unstretched.

(4) Other requirements

The instruments must ensure that the product is measured unstretched according to the intended stretchability for which the instrument is designed.

Area measuring instruments

57.—(1) Operating conditions

(a) Range

Dimensions within the range specified by the manufacturer for the instrument.

(b) Condition of the product

• The manufacturer shall specify the limitations of the instruments due to the speed, and thickness of the surface conditions if relevant, of the product.

(2) MPE

58.  Instrument

• The MPE is 1.0 % but not less than 1 dm².

Other requirements

59.—(1) Presentation of the product

In the case of pulling back or stopping the product, it should not be possible to have an error of measurement or the display must be blanked.

(2) Scale interval

• The instruments must have a scale interval of 1.0 dm². In addition, it must be possible to have a scale interval of 0.1 dm² for testing purposes.

Multi-dimensional measuring instruments

60.—(1) Operating conditions

(a) Range

Dimensions within the range specified by the manufacturer for the instrument.

(b) Minimum dimension

The lower limit of the minimum dimension for all values of the scale interval is given in Table 23.

Table 23

Scale interval (d)	Minimum dimension (min) (lower limit)
d ≤ 2 cm	10 d
2 cm < d ≤ 10 cm	20 d
10 cm < d	50 d

(c) Speed of the product

• The speed must be within the range specified by the manufacturer for the instrument.

(2) MPE

• Instrument—

  • The MPE is ± 1.0 d.