The quarterly newsletter from Phoenix National Laboratories that focuses on quality, testing technology, and inspection trends
We are proud to announce the renewal of our ISO 17025:2017 Lab Accreditation in April 2022 as a quality testing, inspection and engineering services provider. Perry Johnson Laboratory Accreditation (PJLA) is our accrediting body and performed our latest audit March 22-24, 2022 which resulted in recommendation for re-accreditation. PJLA is an MRA Signatory of the International Laboratory Accreditation Cooperative (ILAC) and of the Asia Pacific Accreditation (APAC) which provides peer evaluations in accordance with ISO/IEC 17011:2017 for Accreditation bodies. The importance of this approval is that an impartial, third-party organization is verifying the protocol of the entire laboratory operations. The procedure for accreditation is in-depth, comprehensive and systematic. The renewal time frame of the accreditation is every two years, incurring an authorization check in between renewals. The focus of the accreditation is divided into three categories: certification of staff, calibration of equipment and proficiency of our testing procedures and equipment. We have been accredited through PJLA since 2012 and rank among a few competitors in the Phoenix metro that hold this level of prestigious accreditation.
The subject of working from heights is a serious matter in industry and construction. In the last decade over 500,000 workers were seriously injured in falls from heights; over 6,000 workers subsequently died. Manufacturing and construction companies must institute an OSHA required training program which addresses the dangers and prevention for those who are at risk working at heights. OSHA requires that fall protection be provided at heights of four feet or more in industry, and six feet in construction. The four potential topics that exist are issues related to: ladder safety, aerial lift safety, scaffolding safety, and fall protection safety.
Ladder safety protocol begins first with the choice of the correct ladder, i.e., step ladder or extension ladder and aluminum ladder versus a fiberglass ladder. Fiberglass ladders are the choice for work that involves electricity while an aluminum ladder would conduct electricity. The duty rating for weight, pad integrity, inspection for debris or spills, safe transportation of ladders and the tagging of unusable ladders are important preventative actions. Workers need to climb carefully and slowly wearing a tool belt. Many suitable ladders provide hooks to hold tools.
Aerial Lift safety imposes the responsibility of the equipment upon the manufacturer, dealer, owner and operator who must consult the user manual. The key concepts in Aerial Lift practices include avoiding hazardous situations, performance of a pre-operation inspection, performing function tests prior to use, inspection of the workplace, and usage of the machine as it was intended only. This procedure must be implemented prior to each work shift.
It is estimated that 2.3 million American construction personnel work on scaffolds, which is 65 percent of the construction industry. Every year 4500 injuries and 50 deaths occur involving scaffold accidents. For hazard protection the employer must provide daily onsite inspection of scaffolds assuring they are planked. Scaffold planks are temporary structures used by constructors for support during building construction. These planks are either made of timber or steel and the type of plank used will depend on the type of construction taking place. Fall dangers, using designated areas for egress, rolling scaffolds, and personal protective equipment are all outlined under OSHA guidelines.
Fall protection safety is defined as the safeguard of workers in industry who are on the job at four feet heights and in construction at six feet heights. Fall prevention includes engineering components such as handrails and guards. Fall arrest systems are designed for a safe stop should a worker fall, supplying harness, connectors, anchorage and a rescue plan. They take into consideration arresting forces, required clearances and swing fall dynamics that account for 5,000 pounds of force. The required clearance for a safe fall is a total of 12.5 feet, using a six-foot shock absorbing lanyard connected to a dorsal d ring and anchored at shoulder height. The anchorage point needs to be positioned to a point directly above to reduce the risk of a swing fall which could cause serious injury. A full body harness is required that provides freedom of movement, comfort and maximum protection with locking snap rings, carabiners and d ring larger than snap ring to prevent rollout and disengagement. Lastly, OSHA requires that a Rescue Plan is mandatory, calling 911 and annual inspection of the equipment. A comprehensive training program should be developed to create the knowledge and skill base to keep workers safe working at heights.
Prior to working from heights, each person is to perform a job safety analysis to determine the appropriate fall protection that needs to be used. This may be done individually, or with the assistance of a safety director. It is PNL’s ultimate goal to work safely in all conditions encountered in our industry and failure to take the required protections will result in disciplinary actions.
Technician working on a beam
Phoenix National Laboratories has experienced a surge in client demand for projects that require Ground Penetrating Radar (GPR) for concrete coring in the last year! GPR is a nondestructive testing method we provide that many of our competitors do not. It is regularly utilized in countless construction projects.
GPR is an instrument designed to detect electromagnetic contrasts in multiple materials including soil, concrete, and masonry using an electromagnetic pulse of energy sent into the structure under investigation. When the pulse passes from one material type to another, the pulse wave velocity changes. This shift in wave velocity at the boundary between material types causes energy to be reflected back to the receiver and provides a record of the interface. Both the transmitted and received signals are waves. The system utilizes the principle that radio waves travel at different velocities through different materials. Since the velocity is dependent upon the electrical characteristics of that material, the change in that electrical difference can be recorded by the impulse radar.
The most common use of GPR is to detect objects below the surface in a non-destructive way, without the need for coring, drilling, or cutting. Concrete coring experts and construction professionals require a reliable, non-destructive means to locate targets within concrete structures prior to drilling, cutting or coring, and the ability to detect AC power and induced RF energy present in buried utilities.
Highway professionals, engineers and transportation departments require a safe, reliable and non-destructive method to evaluate roads and bridges. Ground Penetrating Radar technology allows them the ability to collect quantifiable data on transportation infrastructure. PNL routinely performs GPR on bridge decks.
PNL provides three concrete testing methods including GPR, Radiography and Pachometer. GPR works best when clear areas need to be found rapidly from topside slabs where cables and reinforcing steel (rebar) are widely spaced. When using 1600 MHz antennae, it is limited to 18 inches penetration, and 1000 MHz antennae is limited to 24 inches penetration. Radiography works best when elements need to be identified such as post-tension cables, pipe or rebar. It is generally limited to 16 inches penetration. Pachometer works best when the presence of a known or suspected element based on drawings or plans needs to be verified such as rebar in a masonry building for code compliance. It is limited to 4 inches to 6 inches permeation.
Example B-scan showing metallic objects at multiple depths
The importance of proper joint fit-up for welds cannot be overstated. Improper fit-up is often a root cause of weld quality issues, particularly if nondestructive examination other than visual is required. The weld fit-up is the foundation of the weld and without a good foundation, problems are likely to arise. This article will focus on a structural application where weld fit-up caused the weld to fail ultrasonic examination.
A column splice was required where the column flange thickness was reduced. The governing code was AWS D1.1. The contractor used a prequalified joint detail on their WPS as shown in Figure 1. Visual weld inspection was conducted by someone other than the NDE technician who performed the ultrasonic examination.
The lower column flange thickness was 0.980" while the upper column flange thickness was 0.745". The depth of the upper and lower columns also did not match. The welder fit and welded the column as shown in Figure 2.
The NDT technician rejected the weld for incomplete penetration, which was the proper call, however, this weld did not pass visual examination for fit-up conditions and should never have been welded as fit. Instead, the lower flange should have been transitioned to match the upper flange thickness. There are multiple problems with the way this weld was made. Firstly, there is not any prequalified joint detail that matches the as fit condition. Secondly, the full thickness of both members was not fully welded. Lastly, AWS D1.1 does not allow the use of filler plates to fill unequal joints.
Both the welder and visual weld inspector failed to understand the workmanship provisions of the AWS D1.1 Structural Welding Code. The weld should not have been scheduled for ultrasonic examination until corrected. The correct joint fit up should have included some sort of transition to allow the faying surface of the backing to come into contact with both members. Alternatively, a B-U4b-GF prequalified joint that uses no backing could have been substituted to avoid the backing bar altogether. Both options are shown in Figure 3.
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