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Required Site Conditions for Infrared Building Envelope Survey

The requirements listed below are based on current industry standards, including those published by ASTM, IIBEC and Infraspection Institute. Following these requirements will help to ensure optimal conditions and best results.

Required site conditions will vary depending the location of the Survey (interior or exterior) and its purpose.

building-envelope-survey-1Survey Location: Interior of Building

Purpose of Survey: Detect Air Infiltration

Clear Line-of-Sight: Since an infrared imager cannot “see through” objects, a direct line-of-sight is required. Any portions of the surfaces to be surveyed with obstructions, such as cabinets, files or furniture, cannot be surveyed. Should it be desirable to move furniture or wall hangings, this should be accomplished 3 hours prior to the inspection.

HVAC Status: The HVAC system should be operating under normal daytime conditions. This includes operating temperature as well as pressure (neutral, negative, or positive).

building-envelope-survey-5Survey Location: Interior of Building

Purpose of Survey: Detect Moisture Presence

Clear Line-of-Sight: Since an infrared imager cannot “see through” objects, a direct line-of-sight is required. Any portions of the surfaces to be surveyed with obstructions, such as cabinets, files or furniture, cannot be surveyed. Should it be desirable to move furniture or wall hangings, this should be accomplished 3 hours prior to the inspection.

HVAC Status: The HVAC system should be operating under normal daytime conditions. This includes operating temperature as well as pressure (neutral, negative, or positive).

Recent Rain or Active Leaks: The Survey should be conducted when the suspect areas are actively leaking or there has been a recent rain event sufficient to cause subject areas to leak.

building-envelope-survey-3Survey Location: Exterior of Building

Purpose of Survey: Detect Air Exfiltration

Clear Line-of-Sight: Since an infrared imager cannot “see through” objects, a direct line-of-sight is required. Portions of the building that are obstructed by trees, vegetation, or snow cannot be surveyed. Whenever possible, vehicles or building materials should be moved prior to the commencement of the inspection.

Inside/Outside Temperature Differential: For best results infrared inspections require a minimum inside/outside temperature differential of 10C (18F) for three hours prior to, and during the inspection.

Winds of less than 15 mph

No precipitation on the day of the Survey: Moisture that falls during the day of the Survey will interrupt normal solar loading and cooling of the building surfaces. Even if evaporation results in the surfaces drying, the effects of the evaporation can interfere with the thermal images.

building-envelope-survey-4Survey Location: Exterior of Building

Purpose of Survey: Detect Latent Moisture

Dry Building Surfaces: : Building surfaces should be dry at sunrise. Areas that are wet may not undergo sufficient solar loading to create thermal anomalies.

Recent Precipitation: If the surface to be inspected is EIFS, appreciable precipitation should be recorded within a week prior to the Survey. Surfaces consisting of brick, cementitious stucco, concrete, etc. should be inspected within 48 hours of precipitation sufficient to cause building to leak.

Clear Line-of-Sight: Since an infrared imager cannot “see through” objects, a direct line-of-sight is required. Portions of the building that are obstructed by trees, vegetation, or snow cannot be surveyed. Whenever possible, vehicles or building materials should be moved prior to the commencement of the inspection.

Solar Loading: The day of the Survey should be a mostly sunny day, providing good solar loading. A general rule of thumb is if the building surface or a nearby similar surface (i.e. parking lot, street or sidewalk) is warm to the touch, sufficient solar loading has occurred.

Winds of less than 15 mph: During daytime hours and at the time of the Survey, winds should be less than 15 mph. Stronger winds can result in convective cooling effect that may cause thermal anomalies to go undetected.

No precipitation on the day of the Survey: Moisture that falls during the day of the Survey will interrupt solar loading. Evaporation will completely or unevenly cool building surfaces thereby rendering problem areas undetectable.