Material specifications: Envelopes

Contents Sometimes the contents of an envelope affect the acceptance negatively. The following items will not be accepted by the optical character reader: Envelopes that are too rigid (ie they cannot bend) Envelopes that are near the 5 mm thickness with contents that do not fill the entire envelope (for example chequebooks) Envelopes that are near the 5 mm thickness with contents that are loose in the envelope, for example keys, computer diskettes, bottle tops, et cetera Note: Examples may be smaller than actual size envelope thickness. Mass The following masses apply to letters and cards: Minimum Maximum Letters 4 g 50 g Postcards 2 g 50 g Rigidity Letters that are too rigid cannot be mechanically processed or can cause extensive damage to mail-sorting equipment. Examples are: Cardboard filling Pencils Rings Keys Coins Bottle tops or items of metal or plastic Flatness A mail item placed on a flat table should not have a variance of more than 10 mm for letters and printed matter and 8 mm for postcards. Optical character reader acceptance is based on a maximum thickness of 5 mm. To test a sample, use the following die cut: Envelope design Envelope specifications are as follows: Class The paper must be of one of the classes indicated in table 1, as specified by the purchaser. When determined in accordance with the relevant test method indicated in column 10 of table 1, the physical properties of the paper must be free from imperfections that can affect its serviceability and it must accept all common writing media. Colour The colour of paper in classes 2, 3 and 4 must be one of those listed in columns 3, 4 and 5, respectively, of table 1, as specified by the purchaser. White paper in classes 2, 3 and 4 may be overprinted on the side that is on the outside of the envelope, in a solid colour as specified in Annexure A, or the manufacturer may use a paper of the specified colour. Brightness and opacity Paper of class 6 that is not overprinted on the inside to increase opacity must, when determined by means of the relevant test methods indicated in column 10 of table 1, comply with the requirements for brightness and opacity indicated in column 7 of the table. Window material Window material must be glassine or transparent film. The material must be at least 90 per cent transparent. Adhesive Adhesive refers to the adhesive used for the construction of the envelope or for sealing the closure flap, and should meet the requirements described on the next page. Adhesive Adhesive for construction of envelopes Adhesive for construction of the envelope must - ensure bonding; be acceptable and in line with OCR requirements and specifications; and be between the relevant surfaces.In the case of envelopes used with automatic mailing equipment, the adhesive must not induce a degree of curl in the envelopes that is unacceptable to the purchaser and that is not in line with the OCR requirements. Adhesive used for closure flap The adhesive used for sealing the closure flap must be one of the following types, as specified by the purchaser: Rewettable type: Free from toxic and harmful substances. The flap must not become unstuck in the normal course of events, once the gummed area of the closure flap has been moistened and pressed down onto the back of the envelope. The adhesive must also comply with any additional requirements specified by the purchaser. Self-adhesive type: Once the closure flap has been firmly pressed down onto the back of the envelope, the flap must not become unstuck in the normal course of events, unless deliberately opened. Note Synthetic flap adhesives (touch and seal or self-seal) have a shelf life that can be as short as two months under satisfactory storage conditions with regard to temperature, humidity and freedom from dust. Thereafter, the sealing properties could become unsatisfactory. Table 1 - physical requirements for paper (1) The following table sets out the physical requirements for paper: 1 2 3 4 5 6 7 8 9 10 Property Requirements Test method subclause Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7 Class 8 Grammage, g/m²a) Nominalb) Actual, min 60 57 70 67 80 76 90 86 90 86 120 114 120 114 120 114 9.3.3 Bursting strength, kPa, min 125 110 130 150 200 250 300 350 9.3.4 Internal tearing resistance, MD, mN, min - - - - 650 750 1000 1100 9.3.5 Air permeance, um/(Pa.s), max (2) - - 6,8 6,8 - - - - 9.3.7 Brightness, percentage min - - - - - 80 (5) - - 9.3.8 Opacity, percentage min - - - - - 91 (5) - - 9.3.9 Colour (3) White Buff (4), white or tinted (3) Buff (4), white or tinted (3) Buff (4), white or tinted (3) Golden brown Opaque white Golden brown Kraft brown - (1) See table 2 for suggested application of class of paper to size of envelope (2) Only applicable to paper for envelopes used on suction-fed automatic inserting machines (3) For optional colours, as specified by the purchaser (4) For the purpose of this specification, buff, beige and Manila are considered to be the same colour (5) Applicable only to paper that is not overprinted on the inside Table 2: Dimensions of envelopes and recommended classes of paper The following table sets out the dimensions of envelopes and recommended classes of paper: 1 2 3 4 5 Envelope type Size Dimensions mm (1) Recommended classes of paper (2) Banker Pocket C6 DL B6 114 x 162 110 x 220 125 x 176 162 x 114 220 x 110 176 x 125 1(3), 2 and 3 Conventional B6/C4 C5 B5 125 x 324 162 x 229 176 x 250 324 x 125 229 x 162 250 x 176 3, 4 and 5 C4 B4 E4 C3 229 x 324 250 x 353 - - 324 x 229 353 x 250 400 x 280 458 x 324 5, 6(4) and 7(4) Automatic mailing DL - - - C5 Other 110 x 220 100 x 230 115 x 230 120 x 235 162 x 229As specified - - - - - - 3 and 4 (1) The following tolerances will apply: a) Conventional envelopes: Up to and including 150 mm +2/-2 mm; over 150 mm +4/-3 mm b) Automatic mailing envelopes: +2/-1 mm (2) Where paper strength is a consideration, the higher-class numbers should be selected. Some specialised applications may necessitate the use of other classes of paper. (3) Intended mainly for air-mail envelopes (4) The carrying capacity of envelopes manufactured from these materials is in the order of the equivalent of 150 sheets of paper that has a nominal grammage of 80 g/m² and is of the size appropriate to the size of the envelopes.

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