Minimizing Moisture Problems While Adopting the New Green Code

The influence of “green” in health care is not new. Take a look at the evolution of green guidances over the last decade:

• 2002 – Green Healthcare Construction Guidance
• 2004 – Green Guide for Healthcare 2.0
• 2007 – Green Guide for Healthcare 2.2
• 2008 – Leadership in Energy and Environmental Design (LEED) 2008 for Healthcare
• 2009 – LEED 2009 for Healthcare
• 2011 – ANSI/ASHRAE Standard 189.1, “Standard for the Design of High-Performance Green Buildings
• 2011 – 65 new pilot projects under Green Guide for Healthcare 2.2
• 2012 – Life cycle cost analysis for project/product selection under LEED for Healthcare
• 2013 – Second Public Review Period closes for proposed ASHRAE/ASHE Standard 189.3P, “Standard for the Design Construction and Operation of Sustainable Healthcare Facilities”

Also significant in 2012 was the issuance of the new International Code Council (ICC) Green Code (IgCC). A marked step forward for the design and construction community, it is the culmination of work that began under the USGBC LEED program, percolated in the CalGreen Code (California Green Code) and became refined from a code perspective through organizations like ASHRAE. 

The IgCC provides a vehicle for codifying many elements of the LEED rating systems and ASHRAE standards (such as 189.1 in 2011, 90.1 in 2010, and 62.1, also in 2010) that have been issued over the last decade (most of them in just the last three years). Because the adoption of the IgCC is just now beginning to take shape, only a handful of jurisdictions (some local and some statewide) have implemented the code. Most notably, Dallas recently announced that it will adopt the IgCC for all projects beginning in 2013.

Despite health care’s green history, one of the greatest challenges facing the new IgCC is that it has codified the prescriptive nature of previous rating systems. Although standards like LEED are based upon sound building performance principles resulting from consensus amongst health care building professionals, the design community has often forgotten that it still takes the health care design professional to determine that the various credit choices will successfully work together. If this individual is left out of the equation, decisions will likely be made that will virtually guarantee failure and building moisture problems.

The IgCC, along with its predecessors CalGreen, LEED, and ASHRAE 189.1, has encouraged a fundamental shift in the design of buildings that has increased not only building complexity but also the number of potential “drivers” that can act on the building. Both factors lead to a higher risk of building failure. For example, building envelopes that have a greater number of transitions and terminations are more complex, thus increasing the chances of failure in the air, water, vapor or even thermal barriers. Another key building influencer bringing about greater risk is the change in HVAC system design in an effort to meet new energy and IAQ targets.

Equally challenging in the effort to avoid moisture problems under the new IgCC is the shift in products being used in today’s green buildings. The creation of alternative building products as a response to new green initiatives demonstrates an attempt at compliance rarely seen in other segments of the green building community. Much emphasis has been placed on the production of low emissions products such as adhesives, paints and sealants, to name a few. (The actual list of products affected is quite extensive.)

This requirement for using low emissions products in new construction goes back to early LEED requirements. CalGreen continued the tradition when it was issued as code in 2010. ASHRAE also picked up on the topic in its Standard 189.1-2011, requiring many products to comply with low emissions criteria. The marketplace reacted by developing or repurposing low-emission products that were in many cases water-based. Traditional solvent-based products that cured upon application were frequently replaced by water–based products that dried upon application.

Although this shift is intended to improve the indoor environment of the building by eliminating the introduction of products and materials that can release specific VOCs, case studies are proving that significant issues can be associated with these product changes. For example, we have failed to adapt our construction means and methods to meet the needs of products that dry instead of cure. One such case study recently highlighted the challenges facing the construction industry with regards to this issue.

Case Study: Educational Medical Lab

Recently a large educational medical lab in a mid-Atlantic state was nearing the final stages of construction when extensive mold growth was discovered inside the ductwork system. This isn’t good for the construction team. When mold is discovered, it’s so important that it is inspected straight away as it can be dangerous. Some mold can be toxic and can impact the air quality, so it’s important to contact a company like SafeAir Certified Mold Inspection Inc. They should be able to use a range of methods to inspect the mold, such as a thermal imaging camera. This should ensure that buildings are safe.

The building had been designed and was being constructed to achieve LEED Silver. Based upon the architect’s established green criteria, the engineer had dutifully specified ductwork mastic that was water-based and not solvent-based. The reasoning was that solvent-based mastic would release certain undesirable VOCs into the building as it cured. Water-based mastic, on the other hand, dries and as such does not release significant levels of specific VOCs into the building in the process. This design objective was intended to be a part of an overall goal of reducing emissions from materials, controlling pollutants in the building, and complying with codes like the IgCC.

Additionally, the ductwork was being diligently covered with plastic, as was required by the specifications and has also been considered good practice in the construction industry for some time. The combination of ductwork covered faithfully by the mechanical contractor, along with the application of a water-based mastic that dries instead of curing, resulted in mold growth inside the ductwork that cost $1.5 million in remediation before the building was even completed. This unfortunate event also jeopardized the construction schedule, requiring re-work by many of the subcontractors.

What happened here is an intersection of decisions that, while on their own are prudent, together resulted in the unintended consequence of mold growth. The traditional solvent-based mastic would have cured even if the ductwork had been covered, but would have potentially released VOCs. The water-based mastic did not release any VOCs, but remained wet for several weeks inside the covered ductwork, resulting in a costly mold problem.

It is within this environment of combining objectives and decisions that misunderstandings by contractors will continue to be an area of high risk on projects. The risk is that builders are using products quite different from what they are used to dealing with because manufacturing is now done to meet new green objectives. Furthermore, contractors know very little about the performance of these products or their interaction with other products or materials in the buildings. As such, it becomes increasingly difficult to mitigate against potential risks. This is especially true when these new products are being used under varied conditions during construction.

The authors are forensic architects and engineers with Liberty Building Forensics Group, a firm located in the Orlando, Fla., area that specializes in moisture intrusion, mold problems, litigation support/buildings forensics, problem-avoidance peer reviews, commissioning and implementation of green buildings.