In our March 2019 post entitled “Mass Timber Rises to New Heights”, we previewed the upcoming 2021 IBC changes that will allow for up to 18-story mass timber buildings via new Type IV construction types. However, the 2021 IBC is several years from being proposed for adoption within many states. Even in Massachusetts, where it has been established that the 2021 IBC will serve as the basis for the upcoming 10th edition of 780 CMR, the final state amendments are likely at least a year away (and could be pushed further depending on how the COVID-19 pandemic plays out).
Developers, owners, and architects are left wondering: What are the options for those who want to build tall mass timber buildings before the 2021 Edition of the IBC is adopted?
At Code Red Consultants, we suggest approaching the Authority Having Jurisdiction (AHJ) about the prospect of utilizing these recently recognized technologies and methods. This typically occurs under the auspices of IBC §104.11, Alternative Materials, Design and Methods of Construction and Equipment, and it happens either with ‘local approval’ or through an official variance request (the process for which varies by state).
With either path, we offer the following recommendations and considerations:
1. At the appropriate time in the project, proactively seek an audience with the AHJ to vet the concept of the request. Determine whether local approval will be provided or if a formal variance will be required. How will a statement of noncompliance be obtained (which is usually required in order to formally appeal)? Even if the local AHJ is formally denying compliance, having him or her provide support (or at least non-opposition) of the variance request often goes a long way in the appeals decision.
2. Variance/appeals requests take time. Especially in today’s climate, getting an audience with building and fire officials often takes longer than expected. Further, getting through an appeals process requires a knowledge of how the system works to make sure it is being managed effectively. For the sake of the project, establish a realistic timeframe of the approvals process to temper stakeholder expectations.
3. If presenting a request to use the provisions outlined in the 2021 IBC, be prepared to apply all of the 2021 IBC changes related to tall mass timber. ‘Cherry picking’ portions of a new code is typically frowned upon, with good reason – a code is a holistic set of provisions and allowances that work in concert with one another to establish a minimum level of safety. 2021 IBC mass timber requirements that have been overlooked include provisions such as:
a. The Owner retains responsibility for annual inspection and maintenance of fire-rated mass timber structure.
b. Adhesives and sealants are required at abutting edges of mass timber elements.
c. Protection of penetrations and joints in fire-rated mass timber elements is required just like any other rated wall or floor/ceiling, but the catalog of firestopping and fire-rated joints within mass timber elements is still in its infancy. Development and research of such details needs to happen with more attention and earlier in a design process than normal.
d. Fire pump connections require redundancy for mass timber buildings of certain heights (heights less than otherwise required for non-combustible construction).
4. Be prepared to provide additional fire protection and life safety ‘bells and whistles’ as part of approvals negotiation, if requested. Code Red has developed several mitigating solutions when such negotiations are required.
5. Expect to engage a third-party review, both for structural design and fire-resistance/life safety/code compliance.