Infrared Imaging and Spray Testing of Walls
Tip written by: Infraspection Institute
Infrared imaging can be useful for detecting leaks within building sidewalls; however, timing an inspection can be tricky. Controlled wetting of walls can be used to simulate storm conditions during an inspection.
Water spray racks are mechanical devices that permit controlled wetting of a building surface. Spray racks typically consist of lightweight tubing and engineered spray heads spaced at regular intervals. When connected to a water supply and placed in front of a building wall, a spray rack can be used to deliver a deluge of water to an area of interest. The amount of water delivered can be controlled by using different size spray heads and/or varying supplied water pressure.
Spray racks are commonly used for testing the water tightness of curtain walls. During an infrared inspection from the interior of a building, spray racks can provide continuous wetting of walls to aid in leak detection. Spray racks can also be used to uniformly saturate a wall when infrared inspections are to be performed at a later time to detect evidence of latent moisture.
Because spray rack operation requires special tools and presents unique challenges, it is often best done by a qualified professional. Thermographers performing imaging during or after spray testing should keep the following in mind:
- Spray testing can be time consuming due to set up and/or repositioning of spray equipment
- Spray testing can cause significant building leakage requiring an interruption of testing
- Spray testing can be messy; avoid getting your imager wet
- When imaging from the exterior of a building, allow sufficient time for surface to dry and a Delta T to develop
Thermal imaging during spray testing is one of several applications covered in the Infrared Inspections for Home & Building Inspectors training course. For more information call 609-239-4788 or visit us online at: www.infraspection.com
Role of IR Inspections for Electrical Distribution Systems
Infrared inspections can be a valuable tool for detecting problems within electrical distribution systems. Understanding when and where to utilize thermography is key to obtaining maximum benefit.
Infrared inspections can detect and document evidence of loose/deteriorated connections, overloaded circuits, imbalanced loads, harmonics, and defective equipment. In some cases, infrared inspections can detect evidence of problems that may be overlooked by traditional electrical testing. Infrared inspections should be used to supplement, but not replace, regular preventive maintenance.
When setting up an IR inspection program for an electrical distribution system, keep the following in mind:
- Inspections should be performed at least annually
- Inspections should be conducted with the electrical system under normal load
- Inspections require clear line-of-sight to inspected components
- When possible, IR inspections should be performed 4 to 6 weeks in advance of a PM shutdown to allow time to order any necessary parts
- Exceptions should be reinspected after repair to help ensure that repairs were effective
- All new/retrofitted equipment should be inspected within 24 hours of installation
- All findings should be documented in writing in accordance with the Standard for Infrared Inspection of Electrical Systems and Rotating Equipment
Lastly, infrared inspections should only be performed by certified infrared thermographers who possess appropriate safety training and are thoroughly familiar with the system(s) being inspected.
For more information on thermographer training and certification or to obtain a copy of the Standard for Infrared Inspection of Electrical Systems and Rotating Equipment, contact Infraspection Institute at 609-239-4788 or visit us online at www.infraspection.com.
Using an Isotherm Feature
The more things change, the more they remain the same. This timeless observation is especially true when referring to the isotherm feature found on today’s modern thermal imagers.
The isotherm feature found on modern thermal imagers is somewhat of a relic having been around for over 25 years. In simple terms, an isotherm feature allows a thermographer to visually highlight areas exhibiting a similar apparent temperature on the imager’s monitor screen.
Originally designed for the monochrome imagers of the 1970’s, an isotherm is a user-definable, high-contrast overlay generated by an imager’s on-board computer or within image processing software. Prior to the advent of imagers with multi-color displays, the isotherm feature was a necessity for defining areas exhibiting similar temperatures. For other imagers, it was a requisite part of measuring temperature.
With modern thermal imagers capable of providing multi-color imagery and direct temperature measurement, it would seem that the isotherm is a feature due for extinction. There are, however, several instances where an isotherm may still be useful. Among these are:
- The ability to define areas operating within a defined temperature range
- A preset temperature alarm that automatically appears when an object exceeds user-defined temperature limits
- A highlight color that defines hot/cold areas on monochrome images
One should be aware that accurate use of an isotherm is dependent upon proper use of the imager. When using an isotherm, one should practice proper measurement techniques giving particular consideration to viewing angle, spot measurement size and emissivity settings.
Infrared equipment selection and operation are two of the many topics covered in all Level I Infraspection Institute Certified Infrared Thermographer® training courses. Level I training is available at several locations each month and through our Distance Learning Program. For information on thermographer training including course locations and dates, visit us online at www.infraspection.com or call us at 609-239-4788.
Defining Ambient Temp
Tip written by: Infraspection Institute
Ambient temperature is a term which appears in nearly all thermographic reports. However, many thermographers define ambient differently. Some define it as room air temperature while others define it as the temperature inside of the component enclosure.
According to the IEEE, for electrical components ambient temperature is the environmental temperature immediately surrounding the subject component. For devices located within enclosures, this is the temperature within the enclosure while it is closed and operating. For components in free air, it is the temperature surrounding the component.
Infrared inspection of electrical distribution systems is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training or to obtain a copy of the Standard for Infrared Inspection of Electrical Systems & Rotating Equipment, visit us online at: www.infraspection.com or call us at 609-239-4788.
Gauging When IR Inspection Window Opens/Closes
Tip written by: Infraspection Institute
Solar-driven infrared inspections of insulated structures and roofs must be performed when sufficient Delta T is present. Knowing how to gauge when this window of opportunity is present is critical to the accurate collection of data.
Infrared inspections of structures often utilize solar loading to create temperature differentials necessary for the inspection. Common applications include moisture inspections of roofs and walls, structural inspections of CMU walls, and gauging product levels in tanks and silos. Often, these types of infrared inspections are performed during evening hours following a sunny day while the structure is cooling.
The time frame during which solar-driven infrared inspections may be accurately performed is often referred to as the ‘scanning window’. The scanning window is said to be open when conditions permit the collection of accurate data. A number of interdependent factors will determine when the scanning window opens and closes. These include, but are not limited to: target construction, amount of solar loading, local weather conditions, and imager sensitivity.
To determine when the scanning window opens, a thermographer should initially isolate an area with a small delta T indicative of an exception. For moisture inspections, this might be an area that is confirmed to be minimally wet. Using this area as a benchmark, the thermographer can periodically re-check this area during the inspection to determine if a Delta T remains. In general, the disappearance of a Delta T in the benchmark area will indicate that the scanning window is closing.
Infrared inspections of building envelopes and roofs are two of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information on other course offerings, call 609-239-4788 or visit us online at Infraspection.com.
Using Floor Plans to Identify Locations
In a recent Tip of the Week, we suggested using architectural drawings to supplement, or as a substitute for, thermograms for large structures. Structural blueprints can also be used to reference locations when performing infrared inspections of large physical structures.
Within the blueprint set for any large structure are individual floor plans which usually indicate the location of structural columns. Floor plan drawings are customarily laid out with column rows indicated by letters on one axis and numbers on the other. Using a combination of letters and numbers (A1, B1, etc.) to designate columns enables one to universally reference locations within a structure.
Because columns are permanent, their designations will not change over time and will not be affected by changes in structure usage such as floor layout or office location. When utilizing column line drawings to document your infrared inspection, keep the following in mind:
- Prior to the infrared inspection, obtain drawings with sufficient detail
- Verify accuracy of drawings with the subject structure
- Obtain a separate plan for each subject floor
During the inspection, mark the location of exceptions directly on drawings along with thermogram numbers, where appropriate.
Whenever possible, obtain extra sets of drawings to be used as file copies or for field use. When utilized properly, floor plan drawings can serve as valuable reference tools enabling everyone to “speak the same language” when it comes to properly referencing locations.
Infrared inspections of building envelopes is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training or to obtain a copy of the Standard for Infrared Inspection of Building Envelopes, visit us online at www.infraspection.com or call us at 609-239-4788.
IR Inspections of Cool Roofs
Tip written by: Infraspection Institute
Energy and environmental concerns have caused many facility owners to look to their roofing systems for ways to conserve energy. Modern roofing systems known as ‘cool roofs’ can provide savings; however, they can present challenges for thermographers who inspect them.
Over 90% of roofs in the United States are dark colored. On sunny days, temperatures of these roofs can reach 150º to 190º F causing decreased indoor comfort, increased cooling costs, and premature aging of roofing materials. Advances in roofing technology have led to the development of ‘cool roof’ systems that help to solve these challenges.
Cool roof materials have a high solar reflectance or albedo. Compared to conventional roof materials, cool roofs operate at lower temperatures since they absorb less energy from the Sun. Cool roofs also have a high thermal emittance enabling them to radiate well and shed heat quickly after sunset.
Cool roof membranes are usually made of single-ply rubber or plastic materials such as EPDM, PVC, and TPO. These materials are usually white in color and have a smooth surface. Cool roof coatings or paints are an alternative for existing low-slope roofs.
Although cool roof materials are rated to have a high emittance, thermographers should remember that this value is an average emittance value calculated in a laboratory under ideal conditions and at a perpendicular viewing angle. During an infrared inspection, smooth-surfaced roofs appear quite reflective to a thermal imager due to the low viewing angle that is usually associated with inspections performed on foot from the roof surface. This condition is most severe on cloudless nights when atmospheric humidity levels are low.
Due to the low emittance associated with smooth roof surfaces, thermographers can easily miss the small temperature differentials associated with latent moisture. In order to mitigate errors associated with low emittance, thermographers should choose a short wave (2 to 5.6 microns) thermal imager whenever inspecting a smooth-surfaced roof regardless of membrane color or material.
Infrared inspection of flat roofs and proper equipment selection are two of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information or to register for a course, visit Infraspection Institute or call us at 609-239-4788.
Cleaning IR Lenses
Always be sure to follow manufacturers instructions when cleaning infrared lenses and optics.
Lenses and optics are an integral part of any infrared imaging system. Most infrared optics are coated with special anti-reflective coatings to maximize the transmission of infrared energy to the system’s infrared detector. For imaging radiometers, each lens is individually calibrated to the imager.
Improperly cleaning a lens or coated optical element can cause the anti-reflective coating to be damaged thereby changing the transmittance of the lens and the measurement accuracy of the system. If the coating is sufficiently damaged, a costly lens replacement and system recalibration may be required. This recalibration would require sending your imager back to the manufacturer incurring up to several weeks of downtime for your imager.
Imager operation is one of the many topics covered in all Infraspection Level I training courses. For more information on our Distance Learning Program or our open enrollment classes, visit us online at Infraspection.com or call us at 609-239-4788.
Preventing Workplace Falls
Tip written by: Infraspection Institute
“Watch Your Step”. Sage advice that we’ve heard a million times; however, falls continue to be one of the most common workplace accidents. Following a few simple steps can help thermographers to prevent most falls.
Each year falls in the workplace account for over one million injuries and several hundred fatalities. Even a simple slip can cause serious injuries. Many falls can be prevented by following some basic rules:
- Identify all potential tripping and fall hazards before work starts
- Look for fall hazards such as unprotected floor openings/edges, shafts, skylights, stairwells, and roof openings/edges
- Use appropriate fall protection equipment; inspect equipment for defects prior to each use
- Never use boxes or chairs in place of an appropriate ladder or stepstool
- Secure and stabilize ladders before climbing them; never stand on top rung or step of a ladder
- Use handrails when going up/down stairs
- Practice good housekeeping – Keep floors dry and free of clutter such as cords, hoses , and cables
- Keep walkways free of snow and ice
Lastly, be sure to use sturdy footwear appropriate to the task. Work boots and shoes should be laced and tied to prevent tripping and to afford proper support. When it comes to fall protection, an ounce of prevention is worth a pound of cure. For more information on workplace safety standards and fall protection, visit www.osha.gov.
Four Steps to Solving Problems
Solving problems is a constant challenge for most managers. The effectiveness of a manager is directly tied to their ability to accurately define a problem and find the most effective solution. This week’s Tip discusses a simple and proven method for solving even the toughest problems.
Like any project, problem solving involves a series of steps. When completed, the following simple steps should provide an effective solution to nearly any problem. Be certain to complete the steps in order before advancing to the next step.
Step 1: Define the Problem. This is often the most difficult part of solving any problem. Without an accurate problem definition, we cannot begin to find an appropriate solution. When defining a problem, keep it simple and direct, limiting your description to 10 words or less. Once you are certain that your problem definition is accurate, proceed to Step 2.
Step 2: Outline Possible Solutions. Make a list of all possible solutions to the problem you’ve defined. Feel free to brainstorm and let your imagination run free. This is a step for gathering ideas – not for being critical. When appropriate, be sure to seek the input of others.
Step 3: Determine the Best Solution. Drawing from the list generated in Step 2, select the best possible solution to the problem.
Step 4: Implement Your Best Solution. Be sure to monitor the problem and your implemented solution for its effectiveness. If your chosen solution is ineffective, return to Step 3 for an alternate idea.
Solving problems associated with managing an infrared inspection program is one of the many topics covered in the Level III Infraspection Institute Certified Infrared Thermographer® training course. For more information including course locations and dates, visit us online at Infraspection.com
School’s Open – Drive Carefully
Tip Provided by American Automobile Association
By early September, over 55 million children across the United States will head back to school. With 13 percent of those children typically walking or biking to their classes, drivers should be especially vigilant for pedestrians before and after school hours. The afternoon hours are particularly dangerous – over the last decade, nearly one in four child pedestrian fatalities occurred between 3 p.m. and 7 p.m.
Launched in 1946, the American Automobile Association’s School’s Open – Drive Carefully awareness campaign was created as a way to help reduce child pedestrian fatalities and injuries. Here are several recommendations from AAA regarding ways drivers can help to keep kids safe:
- Slow down – Speed limits in school zones are reduced for a reason. A pedestrian struck by a vehicle traveling at 25 mph is nearly two-thirds less likely to be killed compared to a pedestrian struck by a vehicle traveling just 10 mph faster.
- Come to a complete stop – Research shows that more than one-third of drivers roll through stop signs in school zones or neighborhoods. Always come to a complete stop, checking carefully for children on sidewalks and in crosswalks before proceeding.
- Eliminate distractions – Research shows that taking your eyes off the road for just two seconds doubles your chances of crashing. Children can be quick, crossing the road unexpectedly or emerging suddenly between two parked cars. Reduce risk by not using your cell phone or eating while driving.
- Watch for bicycles – Children on bikes are often inexperienced, unsteady, and unpredictable. Slow down and allow at least three feet of passing distance between your vehicle and a bicyclist.
Lastly, always maintain a safe distance from a stopped school bus. Be on the lookout for children boarding or exiting school buses.
Thermography as a Business Opportunity
Tip written by: Infraspection Institute
Savvy business owners are always on the lookout for new business opportunities. Thermography can be a particularly good fit for building and home inspectors seeking to expand their services and generate new revenue.
The past few years have seen tremendous growth in the use of thermography for building inspections. Greater public awareness and lower equipment costs have induced many home and building inspectors, damage restoration specialists and pest management professionals to add thermography to their services.
The income potential for thermographers is significant. Depending upon services offered and rate structure, a single thermographer is capable of generating $250,000 per year in revenue. This potential can be influenced by a number of factors including one’s choice of infrared imaging equipment. Prior to purchasing equipment, one should keep the following in mind:
- Determine your firm’s capabilities with respect to expertise and manpower.
- Conduct a marketing study to determine what services you will offer. In particular, look for services that will repeat annually and/or provide the greatest revenue with the least amount of sales effort.
- Entry level equipment can limit one’s capabilities and revenue potential. Try to anticipate your equipment needs for at least three years and purchase accordingly.
Despite claims to the contrary, thermography is not a ‘point and shoot’ technology. In addition to thorough knowledge of the systems or structures being inspected, thermographers should be trained in infrared theory, heat transfer concepts, equipment operation and selection, current industry standards, and report generation. For those lacking experience, training should be completed prior to purchasing equipment.
Infrared inspection of buildings and their subsystems is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training including course locations and dates, visit us online at www.infraspection.com or call us at 609-239-4788.
The Tortoise and the Hare
Everyone has heard the fabled race between the tortoise and the hare in which the tortoise beats the hare. One of the morals of the story is that a steady pace may be more fruitful than erratic bursts of speed.
Thermographers who perform infrared inspections should keep in mind that a slow and steady pace can lead to victory. Working at an even pace can help to prevent overlooking the subtle temperature variations that often indicate serious problems. Purchasers of thermographic services should bear in mind that the best value is not in the fastest inspection time, but rather in the thoroughness and accuracy of the inspection.
When it comes to your next infrared inspection, beware of the hare. Inspections that are praised more for their swiftness today may be cursed in the future for their costly oversights.
Properly conducting an infrared inspection is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For course locations and dates or information on our Distance Learning courses, visit us online at: www.infraspection.com or call us at 609-239-4788.
Preventing a Transformer Fireworks Display
Infrared inspections of oil filled transformers can help to increase reliability and extend transformer life. Detecting hotspots on the bushings of these transformers may also help to prevent a catastrophic explosion.
Hot spots on transformer bushings are usually due to a loose or deteriorated electrical connection. Frequently, the source of a hot bushing connection is external to the transformer and can be corrected by repairing the defective connection. However, loose connections which originate within the transformer case can represent an extremely dangerous condition.
Loose electrical connections within an oil-filled transformer can lead to a condition known as arcing. When arcing occurs in oil, the molecular structure of the transformer oil breaks down forming several combustible gases. The most significant gases produced are acetylene, hydrogen, methane, ethane, and ethylene.
The amount of gas produced will depend upon the temperature of the arc and length of time; however, even small amounts of gas can lead to a potentially explosive condition. In a sealed, oil-filled transformer these gases can build to a potentially explosive level within a very short time. In short, combustible gases combined with an arcing condition within a transformer are a recipe for potential disaster.
When inspecting oil filled transformers, any inexplicable temperature rise on bushings should be investigated and corrected immediately. Performing a dissolved gas analysis of the transformer oil is recommended if the cause of the problem is suspected to originate within the transformer.
Infrared inspections of electrical distribution systems is a topic covered in all Infraspection Institute Level I training courses. For course locations and dates or information on our Distance Learning courses, visit infraspection.com or call us at 609-239-4788.
Change Routes with the Season
Tip written by: Infraspection Institute
To everything there is a season. The same is true for infrared inspection routes within facilities where equipment or systems are operated seasonally.
Traditionally, many facilities perform infrared inspections on an annual basis. While this approach may detect deficiencies within operating systems, systems not under load due to seasonal or operational conditions cannot be effectively inspected.
Examples of seasonally operated equipment include heating/cooling systems, production machinery, and the electrical distribution system. Effective infrared inspections of seasonally operated equipment begin at the planning stages and should include the following:
- Develop an inventory list of equipment to be inspected
- Group seasonally operated equipment into dedicated routes
- Ascertain operating times for subject systems
- Schedule infrared inspections for the beginning of operating season
- Inspect subject systems while under normal load
Be certain to perform a follow up inspection for all detected exceptions once necessary repairs have been completed. As always, remember to observe all necessary safety precautions before, and during the infrared inspection.
The topic of route based infrared inspections and how to properly organize inspection routes are two of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information or to register for a course, visit Infraspection Institute or call us at 609-239-4788.
Temperature Rise as a Severity Indicator
Tip written by: Infraspection Institute
For years, many thermographers have sought to qualify the severity of detected exceptions by measuring temperature rise. Although this technique is widely practiced, failure to understand key issues can lead to misdiagnoses and unplanned downtime.
For over 30 years, thermographers have frequently attempted to qualify the severity of detected exceptions by comparing the temperature of the exception to similar components under similar load or to ambient air temperature. Although qualifying exception severity may be desirable for maintenance planning, it also involves a certain degree of risk management as some exceptions may rapidly deteriorate and lead to an unplanned outage.
To better understand the risks associated with assigning severity to exceptions based upon temperature, it is important to keep the following in mind:
- For highly reflective targets, small emissivity errors can cause significant infrared temperature measurement errors
- Infrared temperatures are subject to errors due to spot measurement size
- The source of an exception may be contained within a device prohibiting direct measurement at the point of origin
- IR temperature measurement is subject to significant errors due to atmospheric conditions such as wind, solar gain, and moisture
- The temperature of electrical exceptions can increase dramatically and without warning if arcing should occur
- Qualifying exception severity based upon temperature does not consider the potential impact of an unplanned failure
At present, there is no scientific method for accurately predicting time to failure based upon operating temperatures of electrical or mechanical components. In order to reduce the likelihood of an unplanned failure, every exception detected should be investigated for cause and properly repaired as soon as possible.