Version 4.3 adds to the scope of what MASS is capable of handling

We are very excited to announce this new release, available immediately and for free to all current, active license holders. If you are currently using Version 4.2, you can upgrade to Version 4.3 at any time (download and installation instructions are available at the end of this post).

What’s New in Version 4.3?

Click here for the full change log to see all the new and exciting features that are a part of Version 4.3.

Updating to NBCC 2020

MASS v4.3 has been updated to reflect NBCC 2020, with changes focused on serviceability load combinations and seismic provisions. Serviceability checks are now standardized across the software using NBCC 2020 Table 4.1.3.4 SLS load combinations, replacing the previous mix of unfactored, ULS, and SLS approaches. Modules now behave consistently: seismic shear-wall cases continue to use ULS combinations with the NBCC 2020 Seismic Drift Check, while non-seismic cases use SLS combinations with the NBCC 2020 Wind Check; Out-of-Plane Walls and Beams apply SLS combinations to their respective CSA S304-14 deflection limits.

For seismic design, MASS now requires users to input the NBCC 2020 Seismic Category (SC), applying SC-based design limits and using harmonized CSA S304-24 Clause 17 limits to determine the appropriate equivalent provisions of CSA S304-14. MASS also incorporates NBCC 2020 system restrictions for high-importance buildings, including ductility minima for single-storey shear walls, irregularity screening for multi-storey designs, and updated Table 4.1.8.11 parameters. Finally, MASS performs NBCC 2020 Clause 4.1.8.23 performance checks for post-disaster and high-importance buildings, including elastic-behaviour verification (based on user-provided elastic earthquake load) and interstorey drift checks. These updates deliver clearer workflows, consistent SLS-based serviceability evaluations, and fully NBCC-2020-aligned designs.

More information about the updates to reflect NBCC 2020 within MASS can be found here.

Self Weight on Out-of-Plane Walls

MASS v4.3 refines the treatment of Out-of-Plane (OOP) Wall self-weight, replacing the previous approach, which applied the full wall weight as a lumped axial load at the top, with more realistic and flexible options. Users can now select 0%, 50%, or 100% of the self-weight, or choose to apply it at the critical section where moment is highest. MASS also assigns default percentages based on boundary conditions (50% for pin-pin, 100% for fix-fix, fix-pin, and fix-free), all of which can be overridden. These enhancements preserve conservative design paths when needed while allowing a more accurate representation of self-weight effects on OOP behaviour.

Importance Factor

MASS v4.3 simplifies load handling by no longer applying the NBCC Importance Factor, I, to user-entered loads, preventing double-counting and reducing the need for designers to adjust loads before entry. Since NBCC load-generation procedures already incorporate the Importance Factor, the values calculated by the user are now entered directly and used in all ULS combinations. For serviceability checks, MASS automatically converts these ULS-based loads to their SLS equivalents by removing the ULS importance factor and applying the correct SLS factor based on load type and Importance Category (e.g., dividing a snow load using I_s = 1.15 and multiplying by the SLS factor of 0.9). This approach enhances clarity in how loads are treated within MASS.

Other Technical Updates

Other technical updates include the following:

• Enforcement of Maximum Spacing Requirements for Vertical Reinforcement in Non-Loadbearing Walls
• Clause Fixes
• Additional Significant Digits of Loads Entered
• Ability to Rearrange Tabs
• Various bug fixes

More information about these changes can be found in the Change Log.

How to Upgrade

Anyone with a current, activated MASS license can upgrade to MASS Version 4.3 at no extra charge. New releases are included as part of keeping an active license, in addition to other benefits such as comprehensive technical support and course notifications.

To begin downloading MASS Version 4.3, click here to visit the downloads page

Questions about the download, extraction, or installation process? Click here to view the two and a half minute video walk through that will show you how you can install MASS on your computer. There is also a full installation guide available here.

Still have Questions?

Please do not hesitate to contact myself or anyone else in CMDC with any questions or concerns regarding this upgrade.

Canada Masonry Design Centre (CMDC) is the authorized technical service provider for the MASS Software.

Version 4.3 was made possible by the support of our masonry contractor members through CMDC as well as the joint venture partnership through NMDP with CCMPA Canadian Concrete Masonry Producer’s Association – see ccmpa.ca for more information).