Professionalism and TrustMy Account Apply for Membership My Account Apply for Membership National Association of Infrared Specialists 16192 Coastal Highway, Lewes, Delaware 19958 NAIS Core Standards of Practice for Infrared Surveys (CoreSOP) This is the base standard for every NAIS infrared survey. Each NAIS category standard (building envelope, roofing, electrical, mechanical and specialty applications) is an addendum to it and adds requirements for its own discipline. All surveys are also governed by the NAIS Code of Ethics. Section 1: Purpose, Scope and Use 1.1 Purpose. This document sets a uniform, voluntary and defensible minimum standard for planning, performing and reporting infrared thermographic surveys under the NAIS name. 1.2 Alignment. This standard is built on the published practice documents listed in Section 3. Where a referenced standard, a manufacturer's instruction, a client contract or the law is stricter than this standard, the stricter requirement governs. 1.3 Wording. In this standard, shall marks a requirement, should a recommendation and may a permitted option. 1.4 Compliance. A survey is NAIS-compliant only if it meets this CoreSOP and the category standard for the discipline surveyed. A departure is allowed only if the report records it (Section 9.2). 1.5 Exclusions. This standard does not cover medical, veterinary, security or military thermography, or temperature screening of people. Section 2: Definitions Term Meaning Anomaly A surface thermal pattern that differs by more than 2.2 degrees C (4 degrees F) from the pattern expected under the current thermal conditions. Delta-T (dT) A temperature difference. Always state what it is measured between. Emissivity (e) How effectively a surface emits infrared energy compared with a perfect blackbody at the same temperature. Reflected temperature (T_refl) Energy from surrounding objects that reflects off the target into the imager. IFOV Instantaneous field of view: the smallest area one detector pixel can measure at a given distance. Measurement IFOV The smallest object that can be measured accurately, normally about three times the IFOV. NETD Noise equivalent temperature difference: the imager's thermal sensitivity. Qualitative survey A survey that compares thermal patterns without relying on absolute temperature values. Quantitative survey A survey that records corrected temperatures to classify severity. Radiometric imager An imager that stores a temperature for every pixel and allows emissivity and reflected-temperature settings. Thermogram A thermal image, with its stored temperature data. Thermographer The person who operates the imager and is responsible for the survey. Survey Agreement A written agreement signed before the survey that defines its scope, limitations, fee and date. Verification Confirming an anomaly by a second method, such as a moisture meter, load data or inspection. Section 3: Referenced Standards The documents listed here form part of this standard to the extent cited in it, in the edition in force on the survey date. Each category standard lists those it relies on. Edition years are to be confirmed by NAIS before publication. Standard Title (short) ASTM E1862 Measuring and compensating for reflected temperature using infrared imaging radiometers ASTM E1933 Measuring and compensating for emissivity using infrared imaging radiometers ISO 6781 Qualitative detection of thermal irregularities in building envelopes NFPA 70E Electrical safety in the workplace Section 4: Personnel Qualifications 4.1 Level I. May operate the imager and collect data under the direction of a Level II or III thermographer, and may perform routine surveys to written procedures. A Level I thermographer shall not sign a report that classifies findings or gives recommendations. 4.2 Level II. May set up and verify equipment, choose methods, interpret and classify findings, and sign reports within the disciplines they are certified in. 4.3 Level III. May develop procedures and training, review and approve the work of Level I and II thermographers, and resolve disputes about interpretation. 4.4 Certification. A thermographer shall hold NAIS certification, or one NAIS recognizes, for each discipline surveyed. This standard does not set examination content. 4.5 Knowledge. The thermographer shall understand heat transfer, imager operation, the effect of emissivity, reflection and atmosphere, and the equipment or building being surveyed. 4.6 Records. A firm shall keep a current record of each thermographer's certification, training and continuing education and shall show it to a client on request. Section 5: Equipment 5.1 Imager requirements Specification Minimum requirement Thermal sensitivity (NETD) 0.10 degrees C (0.18 degrees F) or better at 30 degrees C Detector resolution 160 x 120 pixels (320 x 240 recommended for electrical work) Spectral range Long-wave infrared, 7.5 to 14 um, preferred for buildings Field of view Able to resolve individual framing members or component detail from a safe distance Radiometric capability Adjustable emissivity and reflected temperature; required for quantitative surveys Image storage Stores each thermogram with its settings (emissivity, reflected temperature, distance, date and time) Visual image A registered visible-light photo, or a separate photo of the same view 5.2 Accessories The thermographer should carry lenses suited to the work, a tripod or stable rest, and a calibrated thermometer, humidity meter and wind meter. Lenses and filters shall be those the manufacturer specifies. A window or filter that changes transmission shall be accounted for in the readings. Moisture meters and other secondary tools shall be in good condition and used as their manufacturers instruct. 5.3 Calibration and verification The imager shall be calibrated by the manufacturer or an accredited laboratory at the manufacturer's interval, and at least every 24 months if none is given. The firm shall keep calibration certificates and show the current one to a client on request. Before each survey day the thermographer shall check the imager against a known reference, such as an ice-water bath or reference blackbody, and record the result. An imager that reads outside the manufacturer's stated accuracy shall not be used for quantitative work until serviced. An imager that has been dropped, repaired or exposed to conditions outside its rated limits shall be checked before reuse. Firmware and software versions used for the survey and report shall be recorded. Section 6: General Survey Procedure 6.1 Survey Agreement and scope Before the survey the thermographer shall agree the following with the client in writing: the property or equipment and anything excluded; the purpose of the survey; whether it is qualitative or quantitative; who provides access, power and a safe means of approach; the conditions required and what happens if they are not met on the day; and the report format, delivery date and limits of liability. 6.2 Safety The thermographer shall follow the site's safety rules and carry out a site hazard check before starting. The thermographer shall never touch or bridge energized components, and shall not open an enclosure unless trained and equipped to do so. Work at heights, on roofs, in confined spaces and near moving machinery shall follow the applicable regulations and the client's rules. The survey shall be stopped if conditions become unsafe. 6.3 Environmental conditions The thermographer shall record the conditions in Section 9.1 and shall not survey outside the limits set by the category standard. Direct sunlight, rain, snow, fog, dust and steam that affect the reading shall be avoided or recorded as a limitation, and strong air movement near the target shall be recorded. 6.4 Imager setup Set date, time and units, and focus every image. Adjust level and span to show the anomaly clearly. Where images are compared, use the same range for each. Enter distance, atmospheric temperature and relative humidity where the imager uses them. View surfaces within 30 degrees of perpendicular where possible, because emissivity falls off at steep angles. 6.5 Emissivity and reflected temperature For quantitative surveys the thermographer shall set emissivity for the actual surface, from a published table or measured against a reference (ASTM E1933). Reflected temperature shall be measured at the site (ASTM E1862) and entered in the imager. Low-emissivity surfaces, such as bare copper, aluminum and polished metal, shall not be read directly. Use a high-emissivity reference where that is safe, or report the reading as unreliable. Glass is opaque to long-wave infrared. The thermographer shall not read through glass. 6.6 Spatial resolution The target of a measurement shall fill more than the measurement IFOV. The thermographer shall record the distance for any image used for a quantitative finding and should image unclear anomalies from more than one angle or distance. 6.7 Verification of findings An anomaly is a lead, not a finding, until it is verified. A finding that is not verified shall be reported as "unverified." Section 7: Reporting A written report shall be produced for every survey. It shall contain: Site and environment. Date, time, air temperatures, relative humidity, wind speed and direction, and solar history for the preceding 12 hours. Equipment. Imager make, model, lens and serial number, the last calibration date, and the pre-survey check result. Personnel. The thermographer who took the images and the one who signed the report, with certification levels. Scope and method. The agreed scope, discipline, whether qualitative or quantitative, and the standards applied. Thermogram documentation. Each finding shown with a thermal image and a matching visible-light photo, with its location. Quantitative parameters. For each measured anomaly: emissivity, reflected temperature, distance, the temperature of the anomaly and its reference, and the dT. Findings. A description, the classification where the category standard defines one, whether and how it was verified, and a recommended action. Limitations. Areas inaccessible, hidden, outside required conditions or outside scope. Signature. The signing thermographer's name, certification number and the date. Section 8: Language and Images A report shall separate observations, interpretation and recommendations. The words "defect," "failure" and "damage" shall be used only for verified conditions. A report shall not give an opinion outside the thermographer's qualifications, such as the structural condition of a building or the presence of mold. Original radiometric image files shall be kept unaltered. Thermograms shall show a temperature scale with the level and span, and compared images shall use the same scale or say that they do not. Section 9: Departures, Limitations and Quality Assurance 9.1 Conditions record. The report shall record the conditions required by the category standard. 9.2 Departures. If a survey departs from any requirement, for example because required conditions could not be met, the report shall list each departure, the reason, and its likely effect on the findings. A report with unlisted departures is not NAIS-compliant. 9.3 Limitations of an infrared survey. An infrared survey measures surface temperature and shows patterns. It does not see through walls, roofs, glass or metal enclosures, and it does not show the cause of a pattern by itself. It reflects conditions at the time of the survey and does not replace inspection, testing or the work of other professionals. Every report shall carry a statement to this effect, adapted to the discipline. 9.4 Quality assurance. A firm shall have a written quality procedure covering calibration, report review and corrective action. A report by a Level I thermographer shall be reviewed, and others should be reviewed by a Level II or III thermographer other than the author. 9.5 Records. A firm shall keep the report, original image files, field data, the Survey Agreement and calibration records for at least 7 years, stored securely and kept confidential under the Code of Ethics. Section 10: Enforcement and Review Violations of this standard may result in disciplinary action under the NAIS Code of Ethics, including written warnings, required retraining, suspension or revocation of NAIS membership or credentials. NAIS may audit a sample of a member's reports at any time. NAIS shall review this standard at least every 3 years.

©National Association of Infrared Specialists (NAIS). Permission to copy, reference, or commercially cite this standard in infrared thermography reports or contractual agreements is granted exclusively to active NAIS members in good standing.