One of the most overlooked aspects of industrial maintenance has been the importance and integrity of a calibration program. And, in particular, its physical record. When equipment is tested and certified, the label applied is generally the primary source of information for operators and auditors alike – no matter how strong the ERP system and record keeping, nothing is trusted more than the physical label.
Yet, industrial environments are harsh, ink fades, and chemical exposure is all around. Standard paper sticks fails in days, so opting for the right material for your identification needs is paramount to maintaining safety and compliance. Click here to see the professional-grade options available from Seton.
What is the difference between calibration and verification?
It’s worth refreshing what the labels represent so we can contextualise their importance and the ROI that comes from better documentation. A common to conflate and ask in industrial settings is the difference between calibration and verification?
Calibration is to compare a measuring instrument against a known standard to determine its accuracy and make adjustments from there.
Verification is to check a device against a set of predetermined requirements or specifications to make sure it is performing as expected.
The distinction is needed because relying solely on verification can mask cumulative measurement drift over time and lead to a false sense of security while the tool’s precision silently degrades until eventually it’s rendered inaccurate and unsafe.
The two processes are distinct, but they both require calibration labels that can withstand the environment in which the instrument operates. Which is usually very hot with lots of movement. If a label peels off or the ink fades due to cleaning agents, the verified or calibrated status of the tool then becomes unknown. In the end, beyond safety risks, it’s just more expensive re-testing that could have been avoided with better labels. A false economy.
Assessing environmental stressors
Step one is to perform a site audit to identify the stressors. So, in a laboratory, a label might only face occasional handling and light dust. In a manufacturing plant or an outdoor utility site, the requirements are much stricter.
UV radiation is the primary stressor to identify as it can turn standard plastics brittle and yellow. Unfortunately, it’s not made irrelevant because of the UK’s lack of sun. Exposure to hydraulic fluids, solvents, or degreasers can dissolve standard adhesives and wash away printed text so these are also important. Temperature too, as labels on steam-pipe valves or cryogenic storage units need specialised adhesives that do not lose their tack when heated and cooled constantly.
Common materials for industrial calibration labels
Once you’ve identified the environmental stressors, you can match them to specific material properties. Industrial labels usually have three main types:
- Vinyl: This is the go-to option for versatility and cost-effectiveness. It’s fine for general industrial use. Vinyl is highly flexible, so it’s good for awkwardly curved surfaces like pipes or small hand tools. The flexibility also acts as a slight mechanical buffer, absorbing the physical stress of surface expansion and contraction.
- Polyester: When durability is absolutely everything, polyester is the industry standard. It has a high resistance to tearing and it can easily handle higher temperatures than vinyl. Polyester labels often come with a self-laminating feature too, which is a clear flap that covers the written information to protect the ink from chemicals and abrasion.
- Metalised Polyester and Aluminum: Metal-based labels are great for heavy-duty machinery or equipment that experiences intense heat or steam cleaning. These have a permanent look and feel to them, often mimicking the equipment’s own data plates. Wear and tear will not ruin them.
Adhesion and protective coatings
Of course, the material is rendered unimportant if the adhesive fails. When many machines are powder-coated, cast with a rough texture, or have a thin film of oil that is difficult to remove entirely, adhesive selection is also important.
For low-surface-energy plastics or textured metals, a high-tack acrylic adhesive is usually needed and the straightforward choice. If the environment has frequent washdowns, the adhesive must also be waterproof to prevent edge lift.
In very harsh environments, even polyester might need a secondary layer of protection using overlaminates – these are clear films applied over the label for a physical barrier against scrubbing and UV rays.
It’s also worth considering tamper-evident materials so we can see if they have been altered. These materials will fracture into tiny pieces or leave behind a VOID pattern if anyone tries to peel them off. These give you a visual chain of custody for data integrity and show it has not been broken by unauthorized adjustments.
Selecting the correct label material requires an audit of the environment and appreciating the nuances of the equipment. Then, it’s a matter of choosing materials like reinforced polyester or high-tack vinyl. Facilities need compliance records that last years, so it’s less a question of ROI and performance through manufacturing techniques and more a question of compliance.