What is considered a good coating specification and how is it written?
Specifications are essentially a project “roadmap” that should convey the project scope of work and the requirements in a simple, clear, concise and easy to read format. A well written specification allows the reader to easily navigate, understand, and use the document. The specification wording must accurately present the project requirements in as few words as possible using layman vocabulary rather than in elaborate and difficult to understand terms. The specification should also be written in a logical order that follows the anticipated flow of work as closely as possible. Regardless of the type of coating specification being used, the best specifications are those that clearly state the project requirements one time in a manner free of contradictory and/or confusing information. Specification requirements that are vague, subject to interpretation or contain contradictory or confusing requirements can result in costly rework or premature coating failure.
What is the Difference Between Prescriptive and Performance-based Specifications?
Occasionally you may encounter prescriptive specifications that not only describe the goals and objective of the coating work, but also dictate the means and methods of performing the work. For example, a statement like, “The contractor shall produce a 2-3 mil angular surface profile using G25 steel grit abrasive” is problematic. By specifying the grit size and the surface profile depth, the specifier has created an inherent contradiction that may result in excessive surface profile. Rather, coating specifications should be prepared using performance-based language, which effectively establishes the “goals and “objectives” of the project while the “means and methods” of construction to achieve project compliance are left to the contractor. For example, a typical surface preparation performance requirement in a coating specification may be to abrasive blast clean the steel in accordance with SSPC-SP 10, “Near White Blast Cleaning” and to produce a 2.0-3.0 surface profile; however, the means and methods used to meet those requirements (i.e., blast equipment used, abrasive media size/type, blast nozzle pressures, etc.) will be left to the contractor. The “Construction Standards Institute” (CSI) specification format is a good example to follow.
What are the Typical Sections of a Coating Specification?
A performance-based specification is typically divided into three sections: General, Material/Products, and Execution that address all issues relating to the surface preparation and coating application requirements. If toxic metals are present in the existing coating system being removed, it may be better to include the requirements to control those hazards in a supplemental part of the specification, as they tend to “muddy” the coating specification and cause some confusion. These requirements may include environmental protection, protection of the public, worker safety and hazardous waste management.
What information is typically included in the “General” section?
As the title indicates, the “General” section provides general project information. This section typically includes; a description of the structure being coated (i.e., type of structure, physical location, owner of the structure, etc.), a summary of the scope of work to be performed (i.e., surface preparation method, coating system and number of coats to be applied, and other work to be performed in conjunction with the coating work), the qualifications (i.e., SSPC or NACE certifications/ qualifications) and experience (i.e., similar projects completed. etc.) the contractors and/or their employees must have, definitions of specific verbiage (i.e., Owner, Engineer, etc.) used throughout the specification, submittal requirements, along with other information conveying specific job site/owner policies and/or restrictions such as work hours, use of premises, staging areas, noise levels, etc.
What information is typically included in the “Materials/Products” section?
The “Materials/Product” section identifies the requirements for surface preparation equipment, abrasive blast media, application equipment, protective coverings, containment materials, and waste container requirements. The specific types of equipment, abrasive, protective coverings, containment materials, and waste container types needed to meet the basic requirements are selected by the contractor. This section also identifies the brand names of acceptable coating materials to be applied along with the finish coat color(s).
What information is typically included in the “Execution” section?
The “Execution” section addresses the specific project cleaning and painting requirements including; the responsibility of the Owner or contractor when a deteriorated substrate is encountered (i.e., spalling concrete, severely corroded or perforated steel, etc.); installation and maintenance of protective coverings; treatment of pack rust, weld spatter and sharp edges; pre-cleaning requirements such as pressure washing; restrictions on ambient conditions during surface preparation and coating application; surface preparation requirements and acceptance criteria; storage and mixing of coating materials; acceptable methods of application; coating continuity and coverage; dry film thickness and recoat times; repair of any coating damage that may occur; project cleanliness during work and final cleaning; waste handling and disposal; quality assurance and quality control inspection responsibilities; and the criteria for anniversary and/or warranty inspections.
Who Can Prepare a Coating Specification?
Currently there is no licensure or certification required to prepare a coating specification. Typically, a NACE or SSPC Protective Coating Specialist (PCS) certification is proof of training, but not evidence of competency. However, NACE or SSPC coatings inspector certification (even Level 3-certified) is not; as it is not part of the course curricula or a learning outcome of those courses. The key thing to remember is that when an individual is preparing a coating specification, they are preparing a legal document that can be the subject of law suits if prepared improperly. Knowing what should be and should not be in a specification and properly preparing a document that is free of confusing, contradictory information is of the utmost importance for a successful project.