Writing Safety Into Your Coating Specification
Safety should be a primary consideration in any coating specification, because everyone involved in a coating project has the right to return home at the end of the day in just as good a state of health as when they went to work.
In safety, as for all other considerations pertaining to a coatings project, the specifier must first go back to the design basis before writing a coatings specification for either new project work or maintenance painting. The design basis or equivalent documents contain the owner’s health, safety and environment (HSE) philosophy and requirements, and define how safety considerations will impact:
- The selection of coating materials
- The hazards that applicators may be exposed to during the construction or modification of structures, as well as later on in the life of the structure
Coating Types and Hazards
A number of operators, certainly in Norway, have stopped using polyurethane-based top coats because of the recognized and well-documented risks associated with exposure to isocyanates during application. There are good practices in place for limiting exposure risks for applicators.
It is well recognized that isocyanates can give off toxic vapors when they thermally decompose. Heating can be caused by coating removal with a grinder, or the cutting of coatings during structural modifications—particularly now with the decommissioning of aging offshore structures and facilities. There is a lot of cutting done, usually by gas cutting or grinding, and that heat causes the thermal decomposition of polyurethanes.
In the last few years, certain authorities and operators in Norway have prohibited the use of polyurethanes. That practice is being adopted by other companies operating there.
On a previous project where I was involved, the coating specification required that polyurethane-based coatings not be used. That restriction was actually written into the specification, and implemented by the coating contractor, the main fabricators and the majority of the equipment suppliers for that project. (Learn more about polyurethane coatings and an alternative in Selecting the Right Coating for Your Application: Polyurea versus Polyurethane.)
Such a restriction ensures that anybody who has to work on or modify that particular coating system is exposed to much less risk than if polyurethane coatings were used.
These issues need to be recognized early on in the design of a project, and written into a document like the design basis. Then health and safety requirements will be carried through into the coating specification.
Regulatory Safety Requirements
Another important factor that impacts safety in a coating specification is each country's regulatory or statutory requirements.
For example, if you have maintenance painting being done in a plant in a particular country, then it is easy to incorporate statutory requirements into a project-specific or activity-specific coating specification. It is easy because the plant owner will know exactly what the statutory requirements are. Therefore the owner, the project engineer or the project manager can inform the coating engineer or specification writer exactly what the statutory requirements are. These can then be included and referenced in the coating specification.
However, if a specification is being written for a new-build project, which will have equipment supplied from different regions of the world, it is more difficult to specify. General statements have to be included; for example, "The necessary safety precautions shall be taken, based on the locale where the work is being done."
This can relate to statutory safety precautions required for:
- Proper storage and handling of coating materials
- Correct use and maintenance of pressure equipment, compressors, air receivers, blast hoses
- Correct use of restraining clamps, chains, scaffolding, staging
Factors such as the erection and maintenance of scaffolding are extremely important to worker safety, but not all precautions are mandatory in all countries. For instance, the use of deadman handles on blasting hoses is mandatory in some countries, but not a requirement in other countries.
On a project where I participated, the use of deadman handles was not required by local regulators, but the owner asked for it to be implemented and it was. In this way, the owner was demonstrating "duty of care" for the blasters doing that particular work.
Other requirements may be written into the specification to protect personnel against:
- Damage to hearing, eyesight, respiratory system
- Explosive atmospheres
All of this has to be written into the coating specification so that it can then be included in greater detail in the applicator or the construction contractor's procedures.
There are other hazards depending on coating system types, which have particular risks associated with them. For instance, thermally sprayed aluminum (TSA) or thermally sprayed zinc (TSZ) require ear protection. (Read Using Metallization (Thermal Spraying) as Corrosion Prevention for more information on this coating system.)
Electric arc metalizing equipment can produce very high levels of noise—up to 110 decibels. It is therefore important that thermal spray operators have proper hearing protection that has been tested and shown to be effective.
Figure 1. Light from TSA application necessitates the use of protective eye gear.
Ultraviolet and infrared radiation are emitted during metallizing, so applicators must have air feed hoods or masks with the right filters to protect their eyesight. Other gases are generated, such as ozone and nitrogen oxides, so there has to be adequate ventilation to make sure that all of those gases are carried out from the work area.
All personal protective equipment (PPE) must be inspected at intervals recommended by the manufacturer and replaced when expired or if faulty.
Surface Preparation Hazards
Dust is generated in surface preparation, so there has to be effective dust extraction in the blasting shops or areas where the work is done. Dust has to be extracted by suction, then collected and disposed of in accordance with local regulations. The containment of contaminants is important for worker safety.
Figure 2. Spent abrasives contamination.
Dust, cutting materials, blast media and steel shavings removed from substrates during profiling must be containerized so that they don't escape and affect other workers.
Another aspect that is no less important is to prevent these materials from getting out into the plant and damaging other equipment. That is a big concern, particularly with mechanical and rotating equipment, which can be damaged by abrasives and dust.
Ensuring Safety in Confined Spaces
Another important safety aspect in the coating specification is working in confined spaces. In a refinery or plant, there are pressure vessels, tanks and other equipment that require regular inspection, and the operating company will have very specific confined-space working procedures.
Confined space procedures would consider surface preparation and coating activities performed inside pressure vessels and tanks. HSE procedures would address the need to:
- Clean out internal areas
- Conduct gas testing to ensure that any flammable or explosive vapors are below the lower explosive limit (LEL)
- Use ventilation systems to keep air moving through the work area
- Provide access/egress points like hatches or covers so that workers can get in or out of these closed spaces easily in the event of an emergency
First responders also need proper access/egress to and from tank or vessel interiors, in order to extract people in case of an emergency. Adequate access/egress must be included in the design basis and the eventual design of the pressure vessels or the tanks.
As an example from a past project, there were a number of in-deck tanks built into the drilling module for storing various process materials. Some of the tanks had to be slightly redesigned to create adequate access for future inspections and operations, and to allow space for large air extraction nozzles and equipment to be connected. All of their hatches needed to be redesigned.
This all comes back to the design basis that considers not only the requirements for the operational life of a vessel or tank design, but also what is required for coatings work during new construction and later maintenance painting.
Even though the confined space work may form a very small segment of the overall life of a vessel, it is still an extremely important consideration in vessel design.
If the specification on a particular project has made specific requirements that perhaps result in an injury, it is possible that the writer/owner of that specification may be liable for any damages resulting from that injury. However, if the specification is very thorough and states particular precautions to be taken, and they are not taken, the liability could be with the party that is shown to have ignored those recommendations or requirements.
Safety contributes to overall value, and should not be considered a cost. One of the biggest assets that an owner has is his/her workforce—so without this, nothing happens. It is absolutely vital that the workforce operates in a safe manner so that they can come back to work the next day. (Discover more safety considerations in the article The Dangers of Typical Corrosion Prevention Solutions.)
Working safely is not difficult. It just takes recognition of the hazards by all parties, creation and implementation of the right procedures, and the use of applicable protective equipment. Then safety becomes second nature and a part of the organization's culture.
Written by Mark Davidson, Eng.