PNL QUALITY EXAMINER

PNL will be hosting its highly anticipated Open House on Friday July 26th 3 PM to 7 PM. The agenda will include guided tours by project managers, hands-on demonstration stations, refreshments, gift giveaways, and a raffle. The Tempe Chamber of Commerce will provide the Ribbon Cutting ceremony event taking place at 4:30 PM.

The flow of the event will begin at our mechanical lab and conclude in our training room including snacks and drinks. There will be interactive testing areas in which visitors can test, feel, and observe mechanical demonstrations. There will be tour groups of 8-10 people at a time, circulating in an organized manner through the facility. Testing station areas will be the centerpiece of the tour, highlighting many of our services:

• Mechanical Lab~ GPR/X-ray stations concrete and pipes X-ray
• Special Inspections~ High Strength Bolting, Firestop, Fireproofing, Post installed anchors (proof loading)
• Welding~ QA/QC, Certifications, PQR’s, Computed Radiography, Bend Testing
• Nondestructive~ Conventional UT Thickness, Magnetic Particle, Penetrant
• RT Vault~ General Radiographic Services, Bridge RT
• Advanced Nondestructive~ UTPA, Magnetic Flux Leakage, IR Thermography, Trimble Laser Scanner, Asset Integrity 653, 510, 570
• Metallurgical/Materials~ Scanning Electron Microscope, FTIR, Microscopy, Hardness Testing
• Mechanical Testing~ Sample prep, Hydraulic Load Testing, Bearing pads, Tensile Testing, Rebar Testing, Pressure Testing

The opportunity to showcase our facility with this event is the culmination of the vision and trajectory we have maintained for thirty years. 

Guided wave testing (GWT) has come a long way since its inception, bridging the gap between seismology and practical engineering applications.

The study of guided waves propagating (wave movement) in a structure can be traced back as early as the 1920’s, mainly stemming from the field of seismology (study of earthquakes). Since then, there has been an increased effort on the analytical study of guided wave propagation in cylindrical structures. In the early 1990’s guided wave testing was considered a practical method for non-destructive testing of engineering structures. Today, Guided Wave Testing is applied as an integrated health monitoring program in the oil, gas, and chemical industries.

GWT is often compared to ultrasonic testing (UT). The main distinction between guided wave testing and UT is GWT uses much lower frequencies (10kHz – 1 MHz) than UT. These lower frequencies can travel long distances, where UT utilizes test frequencies from 1 MHz to 10 MHz or higher, and is typically looking for localized defects. The underlying physics of GWT is also more complicated than that of conventional bulk waves used for UT as GWT typically uses torsional and flexural wave modes.

GWT is a screening tool using long range ultrasonics to screen a long run of a pipe for moderate to gross losses in cross section thickness rapidly. It can quickly and accurately locate areas of loss over several hundred feet of piping with minimal insulation removal. Once an area has been identified, a more detailed examination using conventional UT is required to determine the precise metal losses and verify whether the losses are OD or ID related.

Applications include fire protection systems, condensate piping, steam piping, oil and gas piping and piping where accessibility is difficult.

The advantages of GWT are:

• Rapid screening for in-service degradation (long range inspection) – potential to achieve hundreds of meters of inspection range
• Detection of internal or external metal loss
• Reduction in costs of gaining access – insulated line with minimal insulation removal, corrosion under supports without need for lifting, inspection at elevated locations with minimal need for scaffolding, and inspection of road crossings and buried pipes
• Data is fully recorded
• Fully automated data collection protocols.

 Disadvantages include:

• Difficult to find small localized pitting defects
• Can’t pass through fittings such as valves, tees, flanges and other accessories. 
• Can’t find gradual wall loss

For more information about GWT contact: Matt@pnltest.com or pnltest@pnltest.com

The disturbing statistics about working outside in extreme heat is that almost half of heat-related deaths occur on a worker’s very first day on the job. Over 70 percent of heat-related deaths occur during a worker’s first week. Arizona is also mountainous so there can be an additional interactive factor between both heat and elevation sickness to be reckoned with. People who are not used to hot temperatures are especially susceptible as it can take several weeks for your body to adjust to hot weather.

Heat can make you fatigued by causing your body to work harder to cool itself, producing chemical changes to your skin. Exposure to the heat may cause you to sweat more, lose fluids and electrolytes, become dehydrated, which further leads to fatigue, thirstiness and muscle cramping. Excessive exposure to the sun’s ultraviolet rays causes damage to your skin, including sunburn, pigmentation changes, and wrinkles. The human body will work to repair skin damage, which triggers the feeling of tiredness while your body heals.

Construction schedules can make workers feel pressures that cause psychological and behavioral changes and puts them at greater risk to heat exposures because they feel the need to prove they can work hard and don’t take appropriate breaks. They also may not want people to think they are lazy.

There are many adaptations and techniques that can be employed by technicians during the extremely hot months which include:

• Drinking plenty of water
• Getting proper rest
• Eating healthy
• Avoiding drinking alcohol
• Taking breaks often
• Wearing protective clothing
• Applying sunscreen to exposed areas
• Finding shade when possible
• Getting out of the heat during breaks
• Knowing your body and being aware of the symptoms of heat illness

There are five heat-related illnesses whose symptoms need to be monitored so that heat stroke, which is a medical emergency and can be fatal, is avoided. The illnesses, ranging from least to worst are heat rash, sunburn, heat cramps, heat exhaustion and heat stroke; all have symptoms that can include heavy sweating, weakness, nausea, cold skin, headache, and dizziness. If you think you are experiencing heat related illness: stop all activity and rest, move to a cooler place, drink water, juice or a commercial sports liquid. Seek immediate medical attention for symptoms that include cool, moist, pale skin, rapid pulse, elevated or lowered blood pressure, nausea, loss of consciousness, vomiting, or a high body temperature. Never leave someone alone who is experiencing symptoms.

A sizeable percentage of PNL’s work is performed outdoors during the hot summer months. We often provide services out in the open, during the hottest times of each day when other craft workers are not present; especially when we are using radioactive materials. With temperatures continuing to rise each year, we face longer exposures to extreme heat. In 2023 the Phoenix area saw 55 days with temperatures 110-degree F or higher. This 2024 season, we have experienced 18 such days. The City of Phoenix has recently enacted rules for protecting workers from extreme heat while working on City of Phoenix projects, as many other cities across the U.S. PNL has adopted measures for all our projects which include awareness training, heat adaptation practices, and providing water to technicians.

Below are the anecdotal experiences of four of our technicians who were interviewed about how they have learned to adapt to working in extreme heat conditions:

"As a native Arizonan, I have learned to listen to my internal body signals. I always begin proactively the day before by getting good rest, sleep, eating well and drinking lots of water, alternatively with hydration supplements. I drink Gatorade or Pedialyte. These replace sodium and potassium which I lose when I sweat-causing muscle cramps. I must begin this way, or I can never maintain or catch up later in the field."

"I always carry packets of Liquid IV, which is an electrolyte mixture that I pour in my water bottle. Then I refill that with regular water. Most construction worksites are mandated to supply water. I always stop at the gas station on the way to worksite and buy gallons of water."

"I am a native Arizonan, so my whole life I have been aware of the subtle differences I feel when I am pushing past my physical limitations in extreme heat. I was a welder for many years, wearing extremely heavy gear, so I must take breaks, get out of the sun, and even use an umbrella when necessary. It is very important to know your body’s limits. I notice that I am in danger when I feel like I am getting a headache, or my speech is off from its normal cadence."

"One of the projects I worked on involved working seven days a week, 12 hours a day, plus three hours travel time. After experiencing lightheadedness, exhaustion, and dehydration, I went to an urgent care facility. I was diagnosed with heat exhaustion. I have since learned it is invaluable to take care of myself by getting a motel room, proactively drinking water early in the morning before it gets hot. I would recommend technicians not assume that worksites provide food or water, especially in remote worksites like power generation construction; they are often desolate locations without shade from trees."

Streamlined with our theme of extreme heat, we turn our attention to the extreme heat created by the industrial arc welding processes used to join metals in the construction industry.  Steel, for example, has a melting point of 2500°F.  Welders are very familiar with the extreme heat caused by welding and are well trained in protecting themselves from the heat. This article focuses on the provisions for controlling welding temperatures during the welding process.    

There are several temperature controls required to be maintained before, during, and after welding that are dictated by the workmanship provisions of most welding codes. The AWS D1.1 Structural Welding Code - Steel will be the primary code referenced here.  Other welding codes have similar requirements.  

Electrodes

Low-hydrogen electrodes must be purchased in hermetically sealed containers or be baked for two hours at temperatures between 500°F and 800°F for AWS A5.1 coated electrodes and for one hour at temperatures between 700°F and 800°F for AWS A5.5 coatings prior to use.  Once exposed to atmospheric conditions for a certain time, depending on the electrode type, they must be placed in ovens maintained at 250°F.  After a minimum hold time of four hours the electrodes may be re-issued.  If electrodes exceed the atmospheric time limits, they must be re-baked.  Re-baking is limited to one time.  

During the summer hours we often hear from welding contractors that it’s so hot outside that the electrodes do not need be in an oven.  Unfortunately, this is not accurate.  First, the oven temperature for electrodes in storage is 250°F.  Secondly, even when it’s extremely hot, the dew point can be such that there is moisture in the air that can be absorbed by the electrode coatings, increasing diffusible hydrogen in the weld.  

Other electrodes can normally be at ambient temperature before the arc is initiated provided. They are protected and stored so that the welding properties are not affected and that they are dry and in suitable condition for use.  

Preheat and Interpass Temperatures

Base metals must be preheated to the minimum temperatures provided for each material and thickness listed in the AWS D1.1 code. These preheat and interpass temperatures shall be maintained during the welding operation for a distance at least equal to the thickness of the thickest welded part, but not less than 3 in, in all directions from the point of welding.  In addition, welding shall not be done when the ambient temperature is lower than 0°F, or when surfaces are wet or exposed to rain, snow or high wind velocities, or when welding personnel are exposed to inclement conditions.  

Preheat and interpass temperatures will depend on the base material, electrodes, and welding process. Thicker material requires higher preheat and interpass temperatures.  Table 1 represents the range of preheats for category A, B, and C materials welded using a low hydrogen process (reference AWS D1.1 Table 5.8).

Postweld Temperatures

When required by contract documents, welded assemblies shall be stress relieved by post weld heat treatment.  Typically, this requires the weld and base material be heated to a minimum temperature of 1100°F or 1200°F at a specified rate, held at that temperature for a specified time based on thickness, and then cooled to ambient temperature at a specified rate.  

Whether it’s cold or hot outside, welding temperatures are required to be maintained in order to prevent inherent stresses caused by the very high temperatures of welding.