1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ICS 23.020.01 ISBN 0-626-1 1566-3 SABS BS 4994:1987* This standard references other standards First edition Approved by the President of the SABS on 4 Ma
4、y 1998 SOUTH AFRICAN STANDARD Specification Design and construction of vessels and tanks UJ in reinforced plastics V) Published by THE SOUTH AFRICAN BUREAU OF STANDARDS SABS BS 4994 Amendments issued since ublication Amdt No. I Text affected Obtainable from the South African Bureau of Standards Priv
5、ate Bag XI 91 Pretoria Republic of South Africa 0001 Telegrams : Comparator, Pretoria Telex : 321 308SA Fax : (01 2) 344-1 568 COPYRIGHT RESERVED Printed in the Republic of South Africa by the South African Bureau of Standards SABS BS 4994 Notice This standard was approved by the President of the So
6、uth African Bureau of Standards on 4 May 1998. Manufacturers producing vessels and tanks in reinforced plastics to this standard may, under a mark permit issued by the SABS, apply the certification mark as illustrated above to the commodity as evidence to the purchaser that the commodity is being ma
7、de in accordance with this standard and that compliance with its requirements is ensured by tests and inspections carried out by the SABS. NOTES 1 In terms of the Standards Act, 1993 (Act 29 of 1993), it is a punishable offence for any person other than a mark permit hdder to apply a cdiaion mark to
8、 a commodity or to refer to the SABS or any of its standards in a manner likely to create the impression that the commodity has been approved by the SABS. Furthermore, no person shall daim or declare that he or any other person complied with an SABS standard unless a) such daim or declaration is tru
9、e and accurate in all material respects, and b) the identity of the person on whose authority such claim or declaration is made, is clear. 2 It is recommended that authorities who wish to incorporate any part of this standard into any legislation in the manner intended by section 31 of the Act consu
10、lt the SABS regarding the implications. This standard will be revised when the parent document is revised. In the meantime, however, comment will be welcome and will be considered when the standard is revised. National foreword This South African standard is identical with BS 4994:1987 and was imple
11、mented with the permission of the British Standards Institution. The National Technical Committee (TC 2058.6: Fibre-reinforced thermoset plastics products), through Subcommittee SC 2058.6C: Fibre-reinforced thermosetplastics tanks and vessels, has accepted the text of BS 4994:1987, Design and constr
12、uction of vessels and tanks in reinforced plastics, as amended in accordance with amendment 1 (I 990), as suitable for publication, without technical deviation or language editing, as a South African standard, with the addition of a cover page, notice, national foreword and committee list. The South
13、 African Bureau of Standards has in recent years taken over an increasing number of international standards for publication as national standards. In some of the take-over standards, the point (also referred to as a dot or full stop) is used as the decimal sign, and users of these standards are requ
14、ested to read this point as a comma in view of the fact that the comma is the only legal decimal sign in South Africa. It should be mentioned that both the lnternational Organization for Standardization (ISO) and the lnternational Electrotechnical Commission (IEC) have formally adopted the comma as
15、the decimal sign. ISBN 0-626-1 1566-3 SABS BS 4994 The South African Bureau of Standards has adopted certain international standards and has published them as SABS IEC standards, SABS IS0 standards, SABS EN standards, etc. Where reference is made in this standard to an international standard, the re
16、ader is encouraged to investigate the possibility of using an equivalent adopted standard, should one exist. Information on currently valid national and international standards can be obtained from the South African Bureau of Standards. Attention is drawn to the references given at the end of this s
17、tandard. These references are indispensable for the application of this standard. SABS BS 4994 Committee At the time of approval of this standard by Subcommittee SC 2058.6C: Fibre-reinforced thermoset plastics tanks and vessels, the composition of the subcommittee was as follows: Aerodyne Technology
18、 (Pty) Ltd BP Southern Africa (Pty) Ltd Chemplast Marc Etter (Pty) Ltd Department of Water Affairs and Forestry Forgeweld Engineering (Pty) Ltd Fritsch Foellmer Engineering (Pty) Ltd Red Apple Plastics CC SABS T (b) the effect of temperature on the properties of the composite; (c) repeated or altern
19、ating loading. As a result of adopting what was effectively a minimum design factor of 8 and taking into account the other design factors, environmental stress cracking of the laminates in aqueous environments has not been a cause of failure in vessels and tanks produced in accordance with this stan
20、dard. This mode of failure has been a common source of trouble in other laminates. Furthermore, test work has shown that the allowable strains are below the level at which environ- mental stress cracking is likely to occur. It has been assumed in the drafting of this British Standard that the execut
21、ion of its provisions is entrusted to appro- priately qualified and experienced people. NOTE 2. The numbers in square brackets used throughout the text of this standard relate to the bibliographic references in appendix K. Compliance with a British Standard does not of itself confer immunity from le
22、gal obligations. BS 4994 : 1987 Specification. Section one Section one. General 1 Scope This British Standard specifies requirements for the design, materials, construction, inspection, testing and erection of vessels and tanks in reinforced plastics, consisting of a polyester, epoxy or furane resin
23、 system reinforced with glass fibres, manufactured by the wet lay-up process. Constructions both with and without a lining of thermo- plastics are included. It is implicit that vessels and tanks covered by this standard are made only by manufacturers who are competent and suitably equipped to comply
24、 with all the requirements of this standard. Compliance with these requirements may be proven by documentation of past experience, or prototype testing, to the satisfaction of the purchaser or Inspecting Authority, as appropriate (see clause 38). In addition to thedefinitive requirements, this stand
25、ard also requires the items detailed in clause 4 to be documented. For compliance with this standard, both the definitive requirements and the documented items have to be satisfied. This standard covers vessels and tanks subject to tempera- tures between -30 OC and 1 10 OC. NOTE 1. There is experien
26、ce with vessels and tanks at temperatures above 1 10 C but these require special consideration. NOTE 2. The following vessels and tanks also require specal consideration: (a) jacketed vessels and tanks; (b) vessels and tanks for the transport of lquids and gases; (c) buried tanks. NOTE 3. The titles
27、 of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this British Standard the definitions of plastics, resin, thermoset, thermoplastics and reinforced plastics given in BS 1755 : Part 1 apply, together with the following definition
28、s and those listed in table 1. NOTE. Where the words purchaser, manufacturer and lnspecting Authority occur in the text, they are intended also to include representatives of the purchaser-, manufacturer and lnspectlng Authorty. 2.1 cure. The chemical reaction resulting in the final polymerized produ
29、ct. NOTE. It may be effected at ambient temperature or by the use of heat. In certain resrn systems the cure has to be effected in two stages; the first stage may, and the second stage does, involve the application of heat. This second stage is known as the post-cure. 2.2 gel coat. A thin layer of r
30、esin on the surface of a laminate, that may or may not be reinforced with a fabric, tissue or scrim. 2.3 laminate. A resin sheet or moulding reinforced with a form of glass fibre or other suitable material. 2.5 manufacturer. The organization that designs and fabricates the vessel or tank in accordan
31、ce with the purchasers requirements. NOTE. The design and fabrication functions may be carried out by separate organizations. 2.6 purchaser. The organization or individual that buys the finished vessel or tank for its own use or as an agent for the owner. 2.7 lnspecting Authority. The body or associ
32、ation that checks that the design, materials and construction comply with this standard. 2.8 vessel. A closed container subject to applied pressure or vacuum, with or without hydrostatic head. NOTE. The term vessel includes branches up to the first flanged connection. 2.9 tank. A container for the s
33、torage of fluids subject only to its own hydrostatic head and freely vented toatmosphere. NOTE. The term tank includes branches up to the first flanged connection. 3 Nomenclature Several terms relating to the strength and load-carrying capacity of individual layers of the composite laminate are used
34、 in this standard. Some have similar but quite distinct meanings and because of both their similarity and their application, particular care is required in their use. The terms concerned are listed in table I, with their definitions, symbols and units. 4 Information and requirements to be agreed and
35、 to be documented 4.1 Information to be supplied by the purchaser The following information shall be supplied by the purchaser and shall be fully documented. Both the defini- tive requirements specified throughout the standard and the documented items shall be satisfied before a claim of compliance
36、with this standard can be made and verified. (a) Process conditions. (1) Materials to be handled (names, concentrations and relative densities) including likely impurities or contaminants. (2) Design pressure (or vacuum) including test requirements and design temperature. (3) Operating pressure (or
37、vacuum) and temperature. (4) Mode of operation, e.g. process cycling conditions. (5) Any abrasion or erosion problems which may be encountered. 2.4 laying-up. A process of applying or producing laminates in position on a former prior to cure. BS 4994 : 1987 Section one Table 1. Nomenclature, Term Ul
38、timate tensile unit strength (UTUS) Load-limited allowable unit loading Strain-limited allowable unit loading Design unit loading (layer design unit loading) Unit modulus Overall unit modulus Design strength (laminate design unit loading) Unit load I symbols and units Definition The strength of a re
39、inforcement type, expressed as force per unit width, per unit mass of reinforcement The load permitted to be applied to a reinforcement type per unit width, per unit mass of reinforcement, not taking strain into account The load permitted to be applied to a reinforcement type per unit width, per uni
40、t mass of reinforcement, taking only strain into account The load permitted to be applied to a reinforcement type per unit width per unit mass of reinforcement, for the vessel or tank under consideration The ratio of the load per unit width to the corresponding direct strain, in a loaded tensile tes
41、t specimen per unit mass of a single glass reinforcement type The calculated ratio of the load per unit width to the corres- ponding direct strain in full laminate of single or multiple glass reinforcement type The load carrying capacity of a laminate. expressed as force per unit width The force per
42、 unit width carried by a laminate resulting from pressure or oiher loads applied to the vessel or tank Derivation Obtained from the fracture load of a laminate of known construction, in a tensile test Determined by dividing the ultimate tensile unit strength by the design factor, K Determined by mul
43、tiplying the unit modulus, X, by the allow- able strain for the particular laminate layer Whichever is the smaller of US or UL at the design strain, d Obtained from the measured load and strain in a tensile test Obtained from a summation of the products of unit modulus and mass of each glass reinfor
44、cement type in a laminate (see equation (12) Obtained by summing the load carrying capacities of all the layers in the laminate (u, m, n terms). The subscripts indicate a main (ULAM) or an overlay (UOVL) laminate Obtained from the appropriate design calculations for the portion of vessel or tank und
45、er consideration (see section three) Symbol u UL US uz X XLAM (may be identified by further subscript) ULAM U L Q Unit N/mm per kglm2 glass Nlmm per kglm2 glass Nlmm per kg/m2 glass N/mm per kg/rn2 glass - - N/mm per kg/m2 glass N/mm Nlmm width N/mm width BS 4994 : 1987 Section one (b) Site conditio
46、ns. (1) Nature of ambient atmosphere including any extremes of temperature. (2) Superimposed loads, e.g. wind, snow and associated pipework. (3) Loads imposed by personnel during erection and operation. (4) In the case of buried vessels and tanks, soil condi- tions and expected loading, e.g. traffic
47、. (5) Seismic loading. (c) Special conditions. (1 ) Boiling out. (2) Vibration due to adjacent plant. (3) Agitation details. (4) Danger of mechanical impact and damage. (5) Loads imposed during transport. (6) Finish, e.g. if fire-resisting (see clause 8). (e) Details of any special or additional tes
48、ts or inspection required and where these are to be carried out (see clause 33 and 39.1 1. (f) Exemption to apply a pigmented coating to the vessel before final inspection (see clause 33). (g) Facilities for testing (see table 4 and 39.1). (h) Name of Inspecting Authority, if applicable. (i) Require
49、ments for packaging, despatch and installation. 4.2 Requirements to be agreed and documented The following items to be agreed between the purchaser, or the lnspecting Authority, where appropriate, and the manufacturer shall be fully documented. Both the defini- tive requirements specified throughout the standard and the documented items shall be satisfied before a claim of compliance with this standard can be made and verified. (a) Resin system to be used (see 6.1 (a) (b) Use of reinforcing materials other than those complyingwith BS3396, BS3496, BS 3691 or BS 3749, as appropria
