One of the challenges in performing an assessment for mold in a water-damaged building has been the lack of a uniform standard approach. Every building has different construction, and damage may result from one or more causes or contributing factors. Water damage and fungal growth in a building may be localized or building-wide.
How does an indoor environmental professional design an appropriate study given these considerations? That was the task set before the American Standards and Testing Methods (ASTM) Committee D22.08. Previous committees had tackled the issue of indoor mold inside a building as a part of a Phase I Environmental Site Assessment (E2418 – “Standard Guide for Readily Observable Mold and Conditions Conducive to Mold in Commercial Buildings”); but there had not been a standard guide for assessment of fungal growth in buildings.
Let’s start out with a few scientific “givens” – mold is ubiquitous to the environment; it is naturally present in every indoor and outdoor environment; and it can thrive in any environment where there is available, sustained moisture, a suitable food source, favorable temperature and pH. So, it is easy to understand how attempting to derive a strategy valuable to all buildings would not be easy.
ASTM Guide for Mold Assessment
It took several years and considerable review before the ASTM Committee produced the most recent version of the D7338 document, “Standard Guide for the Assessment of Fungal Growth in Buildings.” This ASTM guide, released last year, introduced a basic assessment strategy and a framework for locating and evaluating suspect fungal growth in all types of buildings. The steps in this strategy include:
- A defined scope of work – with a clear statement of the goals and limitations of the assessment
- The collection of background information on the building and building systems
- The formulation of a hypothesis for the presence of moisture and fungal activity
- An on-site survey for fungi, moisture dynamics, and HVAC operation
- Documentation of information and a suitable means for reporting findings and recommendations
In addition, as the need arises, the strategy may include: characterizing moisture in greater detail; accessing surfaces likely to harbor hidden fungal growth; and sampling, as warranted, testing the developed hypothesis.
The ASTM document provides a menu of options for conducting an assessment, but does not recommend or support a specific course of action. It describes the minimum steps and procedures that a professional would use but does not address sampling methodology for mold, how to interpret sampling data, remediation of mold, or how to prevent further growth.
A hypothesis regarding the loss is to be completed either before a site visit or, in some cases, during it. Once the hypothesis is developed, it should be tested and evidence-based conclusions developed based on the on-site inspection. The inspection should include the identification of current water damage, the identification of the potential for fungal growth, the presence of odors, and documentation of moisture damage.
Operational Causes of Mold Growth
The ASTM guide identifies the following eight operational causes of damage to and within buildings that promote fungal growth. However, there may be more than one root cause that needs to be identified and corrected in order to solve a moisture problem in a building.
- Construction Related: Building materials stored open to the elements; products installed with excessive moisture; structural materials installed over a wet surface; infiltration of warm, humid air before mechanical systems are operational; installation of interior finishes before building is sealed; ineffective vapor retarder; insufficient waterproofing
- Envelope Related: Missing or unfinished sealants or gaskets; plugged or missing weep holes
- Wind Driven: Damage on one side of building from improper sealants
- Humidity Related: Condensation of humid air on a cooler structural surface/mechanical system that may occur from outside in a hot, humid climate or inside from a cold climate
- Occupant Related: Errors by building occupants – including failure to use ventilation, running water for prolonged periods, venting water use devices into the attic
- Plumbing Related: Pipe leaks, drain backups, pipe condensation
- Drainage Related: High water table, inadequate or non-functional drain pumps, blocked trench drains, excessive rainfall or snow melt
- HVAC Related: Undersized condensate drainage, excess humidification, insufficient cooling, damaged or plugged cooling coils, systems designed for a different prior use of the space
Once an exhaustive visual assessment has been completed, the ASTM document recommends classifying observations into one of four categories: no apparent fungal growth or water damage, water damage with no visible fungal growth, visible growth with no water damage, and visible growth with water damage. It does not incorporate air or surface mold sampling as a part of a routine assessment. Sampling, if performed at all, is to be used only as a tool to test a particular hypothesis. The ASTM guide references additional studies that may be warranted such as water penetration, air infiltration and infrared thermography.
HETI…Helping Deal with Mold and Water Damage Issues
ASTM D7338-14 attempts to provide a consistent, scientifically sound strategy for locating and evaluating suspect fungal growth in buildings using an approach based on scientific method. It still requires the investigator to make qualitative and quantitative judgments based on the particular circumstances related to the loss.
Addressing losses from water damage and mold is an essential part of our world. Hydro-Environmental Technologies, Inc. (HETI) can assist building owners and property managers – along with their insurance carriers and legal counsel – understand the risk and address the loss from water damage and mold on a timely basis.
Whether it’s mold, PCBs, asbestos, lead-based paint, or other indoor environmental quality issues…HETI is available to help our clients assess and address those risks.