CSA W : The Changes. June 2014

Transcription

1 CSA W : The Changes June 2014

2 Agenda Introduction to the Office of Public Safety CSA W59: History Scope & Application Development Process 2013 Edition: Major Changes Q&A

3 CWB Office of Public Safety The CWB Office of Public Safety was launched in 2012 Our primary mandates are to: To advocate for public safety To educate individuals, government and industry to better understand standards related to welding, manufacturing and construction Promote the value of CSA standards and CWB Certification to industry, regulators, owners and public In partnership with regulators, to enforce the use of CSA standards and certification programs

4 CWB Office of Public Safety To support this mandate, several initiatives have been put in place: Central source of informational resources on CSA welding standards and design/product/safety standards that mandate them ( CWB Mark programs to all companies and individuals to promote their certification and/or knowledge and commitment to public safety Focused outreach programs to specifiers, engineers and government to educate these groups on the value of Canadian standards Central point for complaints and enforcement requests

5 CWB Mark Programs There are 2 Mark programs currently available: CWB QualityMark For fabricators CWB Welding SpecialistMark For individuals

6 CWB Mark Programs Common to both programs: Online application No fee Right to use Mark along with custom identification number on: Marketing material Website Product (QualityMark only) Public listing on website

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8 CSA W : The Changes June 2014

9 A 74 Year History First published in 1940 as the CESA S59 Standard Specification for Metal Arc Welding Buildings & Bridges Pages: 16; Clauses: 40; Price: $0.50 In 1946, the standard was renamed W59 and was expanded to cover buildings and bridges and machinery In 1970, the concept of prequalified joints was formally introduced A total of 9 editions have been published 2013 edition: Pages: 456; Clauses: ~2300; Price: $335

10 Scope & Application Originally developed for bridge and building applications, the scope of W59 has greatly expanded Current applications include: Elevators & escalators Nuclear power plants Electrical transformers Storage racks Cranes, lifts & hoists Offshore structures Blast resistant structures Antennas & communications towers Wind turbines Mobile homes

11 Scope & Application Materials and thickness ranges: In Scope? Thickness Carbon steels Yes 3mm Low alloy steels Yes 3mm Stainless steels No N/A Aluminum No N/A Reinforcing bars No N/A Shear connectors Yes 6mm φ Does not cover: sheet steel, pressure vessels/pipe and other applications with product specific codes/standards

12 Development Process The standard is developed by a volunteer Technical Committee made of representatives from key stakeholder groups: Producers (e.g. fabricators, erectors) Users (e.g. inspection companies, owners) Engineering Consultants (e.g. welding and design engineers) General interest (e.g. electrode suppliers, regulators) Participation by the wider public is done through a Public Review process where anyone can provide feedback prior to publication Changes are driven by: Industry / user feedback New technologies / techniques Industry best practice

13 2013 Edition: Major Changes Changes: Deletion of allowable stresses design methodology (Cl. 4, Annex S) Expansion of materials list (Cl. 3, 5, 11, 12) Expansion of permitted welding processes (Cl. 3, 5, 10) Expansion of prequalification (Cl. 10) Introduction of new hydrogen designator system (Cl. 5) Clarification on welding through shop primers (Cl. 5) Clarification on inspection responsibilities (Cl. 7) Addition of alternative inspection technologies (Cl. 8) Addition of requirements for Offshore Structures (Annex U) Addition of new informative annexes

14 Design Methodology (Clause 4, Annex S) In 1974, the limit states design (LSD) methodology was formally adopted by CSA S16.1, Canada s steel design standard. This was in addition to the existing allowable (working) stresses (ASD) methodology that existed in S16 since In 1977, the LSD methodology was included in CSA W59, in addition to the ASD methodology. In 1984, CSA S16 formally withdrew the ASD methodology, i.e. all structures in Canada must be designed using LSD.

15 Design Methodology (Clause 4, Annex S) CSA W59 continued to permit both systems for the 1989 and 2003 editions, as it was determined that some users specifically for machinery continued to use the ASD method The 2013 edition of W59, formally withdrew the ASD methodology from the standard However, the ASD rules were moved to a new annex (Annex S) Annex S is written in normative language to facilitate adoption should owner or regulator choose to permit this methodology

16 Expansion of Materials (Clause 3, 11, 12) With each new edition, due consideration to new materials to W59 is given The 2013 edition is no exception, with 13 new materials added compared to the 2003 edition These include: A992: Standard Specification for Structural Steel Shapes A524: Standard Specification for Seamless Carbon Steel Pipe for Atmospheric of Lower Temperatures A573: Standard Specification for Structural Carbon Steel Plates of Improved Toughness A1018: Standard Specification for Steel, Sheet and Strip, Heavy Thickness Coils, Hot-Rolled, Carbon, Commercial, Drawing, Structural, High-Strength Low-Alloy, High-Strength Low-Alloy with Improved Formability and Ultra-High Strength

17 Expansion of Materials (Clause 3, 11, 12) For each new material, CSA W59 provides: Guidance on preheat requirements Guidance on electrode strength matching requirements Allowance for the use of prequalified joints However, other materials not listed in W59 may be used if: The material is of equivalent welding quality to those listed Equivalent welding quality is determined by the Contractor s Engineer Approved by the (Owner s) Engineer Equivalent welding quality is established on the basis of chemical composition and carbon equivalent

18 Expansion of Materials (Clause 3, 11, 12) Typically, materials are not removed even when the material specification has been withdrawn W59 is frequently used to strengthen or repair existing structures of any age, therefore, guidance must still be provided for old materials Clause 9 provides specific rules on the repair of existing structures

19 Expansion of Welding Processes (Clause 5, 10) The 2013 edition formally recognized gas tungsten arc welding (GTAW) as a permitted welding process. Processes covered by W59: shielded metal arc welding (SMAW) submerged arc welding (SAW) gas metal arc welding (GMAW) gas tungsten arc (GTAW) flux-cored arc welding (FCAW) metal-cored arc welding (MCAW) electroslag welding (ESW) electrogas welding (EGW) stud welding (SW)

20 Expansion of Prequalification (Clause 10) Significant expansion of prequalified joints was included in the 2013 edition, specifically for: GMAW-P (pulsed mode of transfer) All positions GTAW Flat position only FCAW out of position welding (i.e. vertical, overhead) Additionally, the MCAW and FCAW prequalified joints were separated into two 2 distinct tables for ease of use. MCAW remains restricted to flat & horizontal positions

21 Expansion of Prequalification (Clause 10) What is a prequalified joint? A joint configuration / welding process that has been proven to be repeatable in its application Based on: Testing data from industry Empirical data from industry Testing data from the W59 TC Testing data from the Welding Research Council (WRC) Still must validate: Specific welding parameters Specific abilities of the welder Only Canadian, US and Australian standards include the concept of prequalified joints

22 New Hydrogen Designators (Clause 5) The control of hydrogen (H 2 )is a key factor in ensuring the integrity of welded connections W59 has long recognized this, and made a significant change in how H 2 is controlled in the 2013 edition Previously, W59 considered only 2 possible levels w.r.t. H 2 control: Low-Hydrogen (i.e. CH electrodes) Non-Low-Hydrogen This created some issues including: Lack of differentiation of individual materials degree of susceptibility to H 2 absorption and embrittlement Lack of recognition of what CH implied Lack of recognition of advancements by electrode manufacturers to control H 2 in their products

23 New Hydrogen Designators (Clause 5) Recent editions of CSA W48 the electrode testing/classification standard introduced descriptive designators to communicate the level of hydrogen control The system includes: Designator Control H16 H8 H4 H2 16 ml/100 g of weld metal 8 ml/100 g of weld metal 4 ml/100 g of weld metal 2 ml/100 g of weld metal Better Table 5.3 now provides specific levels of hydrogen control for 4 distinct material groupings GMAW and GTAW are accepted as inherently controlled hydrogen without test or designators

24 New Hydrogen Designators (Clause 5) Table 5.3 (partial)

25 Welding over Primers (Clause 5) Several enquires were received regarding welding over paint and shop primers Previous editions did not prohibit welding over primers, provided weld quality requirements are still met However, the relevant clause Cl was typically interpreted as an outright ban To clarify the position of W59, this clause was revised to provide guidance on what may be acceptable Still recognizes that the Contractor s Engineer has the final authority as to what is acceptable

26 Welding over Primers (Clause 5) The following was added to 5.1.3: Welding through a light coat of shop applied primer may not be cause for rejection and does not require specific welding procedures provided the following conditions are met: (a) shop primer conforms to CISC/CPMA1-73a or 2-75 or as accepted by the Contractors Engineer; and (b) shop primer has been applied in a single coat to a maximum thickness of 100 microns (4 mils.) dry film thickness in the welding area. Note (1) Past experience and practice has shown that welding of joist shoes, joist bridging, steel decking, shear studs and other similar situations to steel coated with a shop primer will not prevent the weld from meeting the acceptance criteria of this Standard.

27 Responsibilities of Inspectors (Clause 7) The changes reflect clarification - not a change - in requirements Several enquires were received around who was responsible for inspection Key concepts All welds must be visually inspected The contractor is responsible for the visual inspection of all welds regardless of any additional inspection required by contract The contractor is responsible to select the visual inspector All other inspection requirements e.g. 3 rd party visual or NDE are as defined by contract

28 Allowance of Alternate Insp. Methods (Clause 8) Up to the 2003 edition, only traditional radiography and ultrasonic inspection methods were acceptable under the standard This no longer reflects significant advances in technologies available to the industry This included new technologies such as: Radioscopy (Real-time radiography) Electronic imaging (digital radiography) Automatic UT Multi probe / array UT Phased array UT Time of flight diffraction (TOFD) UT

29 Allowance of AlternativeInsp. Methods (Clause 8) In response, the 2013 edition permits alternative radiation imaging systems and alternative ultrasonic systems as valid inspection methods provided that: It is agreed to by the Engineer and the Contractor prior to inspection Inspection personnel / operators are relevantly trained Inspection procedures are documented and agreed to by all parties Minimum acceptance criteria laid out by W59 still applies

30 Offshore Structures (Annex U) In 1992, welding requirements for fixed offshore structures were published as a supplement to CSA W59, CSA W59S1 Supplement No. 1, Steel Fixed Offshore Structures In 2004, these welding requirements were moved to CSA S473, one part of the Code for the design, construction, and installation of offshore structures In 2009, CSA adopted an ISO standard (CAN/CSA Z19902) as a Canadian National standard to replace CSA S473 thus forcing the withdrawal of CSA S473 However, the industry wished to maintain the unique welding requirements contained in S473 Therefore, the requirements were reintroduced to CSA W59 through addition of a new annex, Annex U Welding of Fixed Offshore structures

31 Offshore Structures (Annex U) Annex U is written in normative language to facilitate its use when directed through CAN/CSA Z19902 It should only be used when fabricating fixed offshore steel structures The annex goes beyond the traditional scope of W59 as it include requirements for: Welder/operator qualifications Procedure qualifications TKY joints tubular joints

32 Informative Annexes The following informative annexes were included in the 2013 edition: Annex S: provides design provisions for allowable stress design methodology (moved from Cl. 4) Annex T: provides a description and intended use of various GMAW classifications and an overview of the (relatively) new ISO classification system now in use in Canada Annex V: provides a comparative information between current and former electrode classifications

33 Q & A