Sleuthing for Mold

Determining the First Condensing Surface helps point an investigator toward a problem where symptoms might not be occurring at the time of the inspection.

• By John O'Brien
• Jul 01, 2005

YOU wouldn't think Ed Smolinski has much in common with Sherlock Holmes. But upon closer examination, you would realize the president of Allied Environmental Corp. does bear a similarity to the famous fictional sleuth. After all, both men are detectives. Holmes's job, as we all know, was directed at solving mysteries involving robbery, murder, and international intrigue. Smolinski's efforts are a tad less dramatic, but important nonetheless: He is solving the mystery of mold.

This is a critical service and one of many offered by his company. In fact, mold inspection, testing, and remediation are among the primary functions at Allied, along with indoor environmental testing, air quality investigations, and lab analysis. The truth is, mold can be a real "whodunit," presenting a variety of challenges for the professional trying to locate it--or to locate the places where it is most likely to occur. It is an important mystery to solve because mold not only can be unsightly and foul-smelling, but also it can cause substantial damage to a building's infrastructure. Even more troubling are the health problems associated with this unwanted growth.

"Moisture is the strongest indicator of mold, but it can sometimes be difficult to detect," said Smolinski, whose company serves commercial and residential customers in the metropolitan New York area. "Depending on the temperature and the weather conditions, you may not be able to find the presence of moisture at the time of an inspection. Perhaps you examine a cement wall during the summertime. The wall is suspect and may be presenting moisture, but during the heat of the day the moisture has dried up. Nothing will register on a standard moisture meter."

As a result, the proficient investigator must resort to other methods for clues, aside from direct observation of moisture or moisture measurement. One such method is the detection of a room's First Condensing Surface (FCS). This is usually an exterior concrete wall, steel beam, or metal pipe connected to the outside of the structure. Usually found in basements, these subterranean surfaces are in direct contact with the consistently cool dirt on the exterior. These surfaces are the locations where condensation happens first, based on the warmth and relative humidity of the interior air.

The cooler surfaces attract moisture from the air, which condenses on the object's interior face. These surfaces can also be wooden or glass and above ground. Most frequently noticed by the homeowner would be the condensation on the inside of a bathroom's window following a hot shower on a cold day. The more this occurs, the more moisture soaks into the window's sill, leading to a mold condition inside the exterior wall. Determining the FCS will help point the investigator toward a mold problem that is not visual or one where the symptoms might not be occurring at the time of the inspection. The concept is to identify the surfaces most prone to condensation as a precursor to moisture and, ultimately, mold.

It should be noted that the difference between whether mold does or does not appear is quite literally the difference between night and day. In the evening, people tend to turn down their thermostats to conserve heat. Consequently, the air temperature drops, particularly around the basement or window sills. Many of these surfaces will then come closer to approaching the dew point, resulting in condensation and presenting the perfect environment in which mold can grow and flourish.

FCS is also important to understand when trying to determine why mold is growing on one patch of wall or only along the wall-ceiling joint. It is likely the surface of the wall is cooler than the room air because of a gap in the insulation or because the wind is blowing through cracks in the exterior of the building. The bottom line is, anywhere you notice a region with a high dew point, there's an excellent chance some microbial matter will appear. Consequently, if the technician can determine relative humidity and air temperature and can calculate dew point, it is possible to determine whether a surface is prone to condensation and, subsequently, mold.

Choosing an Instrument
Realizing the detection of FCS was important to identifying and remediating these mold mysteries, Smolinski knew it was time to upgrade the instruments his company was using. He could consider a wide spectrum of instruments and accompanying features, but that fact that the measurement of FCS was such a high priority narrowed his choices substantially.

Smolinski ultimately settled on a portable digital psychrometer used to measure temperature, relative humidity, dew point, wet bulb, and dry bulb. The psychrometer he chose also was equipped with a built-in infrared thermometer; this infrared thermography capability would allow him to observe surface temperatures quickly. More importantly, it would calculate the dew point and perform a differential analysis between the surface temperature and dew point.

"Essentially, I now had a simple method of performing thermal imaging," said Smolinski. "Thermal imaging cameras are now being marketed to be used in the identification of potential mold areas. The psychrometer I was using did the same thing but at a fraction of the cost."

Ease of use in a psychrometer is a crucial benefit, he said. "The instrument provides a direct reading on inspection. It's not necessary to bring it back to a computer to download for further analysis. I was able to consolidate several instruments into one. Because you don't have to take out several pieces of equipment, there is a time savings, as well."

In the end, any instrument Smolinski employs in the field must feature a simplicity that can be appreciated by the customer as well as the technician. "I like instruments that are extremely straightforward and easy to explain to customers," Smolinski said. "In this case, the measurements and differential calculation are simultaneously displayed on the instrument. You can tell them, 'Here is the temperature of your cement floor, here's the amount of humidity in the air, and this is the ambient temperature that will cause the floor to start sweating.' "

The particular psychrometer Smolinksi uses is also capable of pinpointing thermal bridges in a room conducting heat, another factor in the creation of mold. Thermal bridges are regions of relatively high conducted heat flow in a building envelope and can come in almost any form--concrete, steel framing, voids in insulation, joists, etc. A classic example of a thermal bridge is the wood stud of a typical exterior frame wall where insulation is installed between studs in the wall cavity. The wood stud has a greater conductivity to thermal flow than the insulation and, therefore, provides an easy path for the cold to bridge the wall. The result is a cold spot at the interior face of the gypsum board where it is in contact with the stud. Having the ability to locate these thermal bridges is crucial to solving a mold mystery.

Smolinski even stretches the use of his psychrometer to include bacteria analysis, because bacteria are highly dependent on the presence of moisture. In fact, the instrument can be used for general indoor air quality inspections, identifying a wide spectrum of moisture dynamics and unhealthy conditions. The quest to solve the mystery of mold continues. However, the instrument that Allied will use to solve it is no mystery at all.

This article appears in the July 2005 issue of Occupational Health & Safety.

This article originally appeared in the July 2005 issue of Occupational Health & Safety.