Bridge coatings — regulations and specs

by Bernard R. Appleman

Several years ago, the New England states initiated a program to standardize the painting systems for new bridges. The goal was to reduce testing costs and to minimize problems with untried painting systems.

Engineers in departments of transportation from Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont jointly developed a rigorous performance specification for a three-coat system. The system consisted of inorganic zinc-rich primer, an epoxy intermediate, and a polyurethane topcoat. The testing included laboratory tests (e.g., salt fog, and combined ultraviolet radiation and condensation testing), tests on the liquid paint (e.g., viscosity, density), as well as a three-year performance history. The program coordinator is Alan Rawson of New Hampshire DOT.

Based on the program’s success, the American Association of State Highway Transportation Officials adopted a similar system under the National Technical Product Evaluation Program. The effort is chaired by Richard Hanlon of West Virginia DOT. AASHTO drafted a new provisional recommended practice (RP30-95 — Evaluation of Coating Systems with Zinc Rich Primer — expected to be finalized this year.

AASHTO will establish criteria for approving laboratories. Paint manufacturers will then be able to select an approved laboratory to perform this testing. The tests are paid for by the manufacturer.

Coating regs

After almost a two-year delay, EPA has again targeted bridges and industrial structures for new regulations regarding lead paint removal. At a September Washington hearing and again at the SSPC ‘97 Conference in San Diego in November, Ellie Clark of EPA’s Office of Pollution Prevention and Toxic Substances described the agency’s plans. Late this year, a draft rule is expected, which will outline requirements for training and certifying individuals and firms engaged in lead paint activities on bridges. Presently, several states (including New Jersey, Maryland, Virginia, and Missouri) require painting and other contractors to use trained and certified supervisors and trained workers for removing lead paint, dismantling lead coated structures, or for other maintenance work. The EPA rule is expected to be finalized in late 1999.

picture caption:  Maryland is just one of the DOTs that helped develop a rigourous performance specification for a three-coat system.  The system consists of inorganic zinc-rich primer, an epoxy intermediate, and a polyurethane topcoat.

VOC regulations

Two years ago, EPA proposed a rule limiting the VOC of all field applied coatings, including bridge coatings and traffic markings. The proposed levels are 3.75 lbs./gal. for bridge paints and 1.25 lbs./gal. for traffic markings. The latest information from EPA is that this rule will have few changes for these two categories.

Many DOTs have taken steps to conform, but this may not be true for counties and smaller agencies who may not be fully informed about the rule and its impact. The rule is expected to be effective in one year from its issue date of late 1998.

EPA also announced its intent to revise the regulations on VOC for shop applied coatings. The agency has started meeting with interested stakeholders including SSPC.

The controversial July 1997 EPA regulations also lowered the level of ozone and established new requirements for particulates smaller than 2.5 micrometers. These rules are not expected to have significant impact on bridge painting for several years.

Other projects

The Transportation Research Board has several projects of interest to bridge painting. A synthesis study on bridge protection systems, authored by Tom Neal, formerly of the Virginia DOT, is nearing completion. This report will describe alternate protection technology such as thermal spray metallic coatings and powder coatings. It also documents DOT usage and experiences with conventional and new technologies over the last five years.

A new NCHRP project specifically addressing the technology of thermal spray coatings has been initiated. Laboratory and field evaluations will determine the viability, practicality, and cost effectiveness of this technology. The impetus for this project has been from FHWA’s field test panel evaluations, improvements in the equipment, and reported successes from other industries (e.g., hydraulic structures). The project is expected to take about 24 months.

Certified contractors

Nearly a decade ago, SSPC established the Painting Contractor Certification Program to improve the quality of paint contracting work. Numerous DOTs are now requiring painting contractors to become certified under SSPC’s QP-1 (general qualification for cleaning and painting) and SSPC QP-2 (qualification for removing lead paint) prior to submitting bids on bridge painting contracts. These include Connecticut, Maryland, New York City, West Virginia, Illinois, North Carolina, Florida, and Oklahoma. A milestone of 100 certified contractors was reached last year. Major enhancements of this program include stricter enforcement criteria and provisions for unannounced audits.

Last year, SSPC introduced a similar program for qualifying shops (e.g., fabricators who paint bridges). SSPC is presently working with the American Institute of Steel Construction to coordinate the SSPC program with the AISC’s program for Sophisticated Paint Endorsement. Both programs offer bridge agencies a means to assure better quality painting work in the shop. The joint AISC/SSPC Task Group is chaired by Eric Kline of KTA-Tator, Inc.

Research

At a recent SSPC conference, Bob Kogler of the Federal Highway Administration described two upcoming Federal Highway projects. In August 1997, FHWA initiated a program to identify novel technologies to reduce painting costs. FHWA is seeking input from other industries and any individuals or firms involved in engineering, development, or evaluation of these technologies. In regard to evaluation of waterborne industrial maintenance coatings, the FHWA is seeking information on availability of waterborne coatings containing non-toxic inhibitive pigments. FHWA is tentatively planning a laboratory testing program accompanied by an exterior exposure of panels in various locations. The project coordinator is Dr. Shuang-Ling Chong.

The FHWA is working with the National Highway Institute to develop a four-day training curriculum for engineers and specifiers responsible for lead paint removal projects.

In addition, the FHWA has completed several studies with reports available to describe results, including the following:

1. Guidelines for repair and maintenance of bridge coatings: Overcoating (FHWA Report RD-97-092).

2. Guidelines for cost effective lead paint removal: FHWA Report RD-94-99 (SSPC Report 96-06).

3. Environmentally accepted materials for the corrosion protection of steel bridges (FHWA Report RD-96-058).

The bridge painting community (including DOTs, FHWA, AASHTO and other agencies, private industries, and associations) has made significant advances over the last several years in the technology and the practice of bridge painting and paint removal. Many of the items have been documented in reports and standards or are also available on the Internet.

Dr. Bernard R. Appleman is executive director of SSPC: The Society for Protective Coatings

Reprinted from Better Roads Magazine
March 1998