BS 4060:1989 pdf download.Pressed wool felts.
4 Designation
Felts shall be designated by a condensed technical description (see Table 1 and Table 4) containing the following:
a) a first letter to indicate whether the felt is general purpose (A) or precision (B);
b) a number, consisting of two digits, to indicate the minimum percentage wool content;
c) an oblique stroke;
d) a single digit number, 1 to 8, to indicate the hardness or density grade;
e) a letter to indicate the colour white (W), grey (G) or dyed (D);
NOTE If appropriate, interested parties may agree to include the additional designations in Table 6 and Table 7 to indicate that particular chemical and/or physical requirements have been
complied with (see 5.4 and 5.5);
Examples
A75/1W indicates the felt to be general purpose, with 75 % wool content, extra hard and white.
B97/1G6.1-6.6 indicates the felt to be a precision felt with 97 % wool content, extra hard, grey, having a minimum breaking strength of 5.5 MPa and having chemical properties conforming with 6.1 to 6.6 of Table 6.
5 Performance
5.1 General purpose felts
General purpose felts, including packaging felts,shall comply with Table 1 and Table 2.
NOTE Commonly manufactured thicknesses are 1, 3, 5, 10, 15, 20 and 25 mm but other thicknesses may be specified by the customer.
5.2 Decorative felts
Decorative felts shall comply with 5.1 and shall, additionally, meet the minimum colour fastness
ratings detailed in Table 3 (see also C.3.3).
5.3 Precision felts
Precision felts shall comply with Table 4 and Table 5.
5.4 Chemical properties
If felts are required to have particular chemical properties, the felts shall comply with the relevant
requirements of Table 6.
NOTE 1 The purchaser should specify whether any particular chemical properties are required (see Appendix A).
NOTE 2 For MoD purposes, general purpose felts and felts for aerospace purposes should comply with 5.1, 5.3 and Table 6.
5.5 Physical properties
If felts are required to have particular physical properties, such as breaking strength and oil
retention, the felts shall comply with the relevant requirements of Table 7.
NOTE The purchaser should specify whether any particular physical properties are required (see Appendix A).
5.6 Special finishes
Felts shall be manufactured either with or without special finishes imparting, for example, rot, mildew, moth, flame or water resistance, or a combination of these properties.
NOTE 1 The purchaser should specify whether any special finishes are required (see Appendix A).
NOTE 2 For aerospace purposes, felts should be rot-proofed (see 3.7 of Table 6) in accordance with PCPL (normal process) of BS 2087-1.
6 Inspection, sampling, conditioning and testing atmosphere
6.1 Inspection
Each manufactured piece shall be visually inspected for defects, e.g. permanent ridges and/or creases and holes.
NOTE 1 Interested parties may agree to the nature and number of defects which may be permitted, on the marking of their positions in the roll or sheet and on the appropriate
allowance to be made.
NOTE 2 Felts for MoD purposes should be substantially free from holes.BS 4060 pdf download.