b'2020 NATIONAL BUILDING CODEThe rewritten section on airtightness nowDURABILITY To remedy this, NRC and CSA are currently includes requirements for how assembliesDurability of materials used for environmentalrewriting S478 to publish it as a standard in must perform to achieve an acceptable levelseparation in the building envelope has beentime to be referenced in the Part 5 Appendix of of airtightness. Up to this point in previousan issue that the Part 5 Committee has pushedthe 2020 Code. This step will have a signifi-editions of the Code, the requirements focusedfor at the NBC Committee level for a numbercant impact on the next Code cycle. For the only on materials with appendix notesof years. In the Committees opinion, durability2025 code, the 478 standard is likely to be suggesting approaches covering assemblies.of materials is of great importance when consid- referenced in the body of Part 5 and durability For the 2020 code, codified requirements forering environmental separation and aspects ofwill be considered a necessary part of building assemblies will be included. health and life safety. envelope design.Part 5 includes a table of standards forIn the 2015 edition, a reference to CSA S478WOOD CONSTRUCTION UP acceptable materials that must be met if thoseGuideline on Durability was included for theTO 12 STOREYSmaterials are used in environmental separa- first time in the Appendix for Part 5. However,The changes in the 2020 NBCC will increase tors. For the 2020 NBCC, there have beenbecause the CSA document was only a guide- the height of wood construction buildings up significant revisions or replacements for thoseline, it was not considered appropriate forto 12 storeys. For structures above six storeys referenced standards. jurisdictions to enforce. and up to 12 storeys, the structure must be made with mass timber construction. Up to B.C. IS A LEADER IN WOOD BUILDING CONSTRUCTIONsix storeys, the Code allows the use of light wood framing. AND CURRENTLY HAS AN 18-STOREY DEMONSTRATIONThe 2020 NBCC refers to encapsulated mass BUILDING ON THE CAMPUS OF UBC. BECAUSE OF THEtimber construction, a laminated engineered wood type that has both strength and fire PROVINCES LEADERSHIP IN THIS AREA, B.C. HAS BEEN GIVENratings. Encapsulated refers to mass timber PERMISSION BY NRCC TO BE AN EARLY ADOPTER OF THEthat is coated with materials such as Gyproc or concrete so it resists fire spread. Mass timber 2020 NBC 12-STOREY WOOD PROVISIONS.must have a minimum thickness of 96 millime-tres and a fire rating minimum of 50 minutes.The changes to the wood section do not have an impact on Part 5. In fact, B.C. is a leader in wood building construction and currently has an 18-storey demonstration building on the campus of UBC. Because of the provinces leadership in this area, B.C. has been given permission by NRCC to be an early adopter of the 2020 NBC 12-storey wood provisions. The B.C. government is currently working with municipal governments who want to opt into this initiative.The 2020 NBCC is expected to be published Whats on the in December 2020 following a final public consultation in the fall of 2019 that is restricted outside does to reviewing the standards to be referenced in the new edition. The NBCC is developed by the count. Canadian Commission on Building and Fire Codes and issued every five years by NRCC. Once the 2020 Code is published, B.C. will be looking at the provisions in the new edition of the Code for inclusion in the 2023 BCBC.The challenges for the building envelope industry going forward are to codify how to deal with airtightness in buildings and address in the Code the durability of materials because of its impact on the health of building occu-pants, says Watts. For more information on the 2020 NBCC and a copy of the latest draft of the Code, contact manifesthomes.ca | construction management 604-726-2013NRCC by phone at 1-877-672-2672 or email info@nrc-cnrc.gc.ca.16 BCBEC ELEMENTSA BCBEC PUBLICATION'