Table of Contents
Table
of Contents
1. Applicable Sections
of the Code. 1
2. Executive Summary. 1
2.1. Description of
Issues. 1
2.2. Recommendations
for the Code. 1
3. Scope of Work. 1
4. Deliverables. 2
5. Detailed Project
Description. 2
6. References. 2
7. Appendices. 2
1506.4 1506.7
1517.5.1 1517.5.2
Mark
Zehnal agreed to serve as the Roofing TAC point of
contact. UF has conducted a literature search on the subject of corrosion of
metal fasteners. UF is in discussions with a survey company to determine an
appropriate survey methodology and scope within the performance period and
budget. UF worked with the DBPR to secure a list of potential survey contacts. The
development of survey questions is currently in progress, and will be presented
to the Roofing TAC for comment. The survey will commence upon mutual agreement
of the survey methodology and contents among UF, the Roofing TAC, and the
survey company.
·
Anecdotal information indicates
that corrosion of fasteners used to secure metal ridge vent system
on shingle and tile roofs has been observed
across a range of installations, specifically for electro-galvanized fasteners.
·
The problem is significantly more serious in
coastal environments due to
presence of chloride ions
·
Increased manufacturing of these products
outside the United
State may be attributing to the
problem
No
recommendations at this stage
·
Consult with the Roofing
TAC on writing questions and identifying audience
·
Perform literature search for relevant
context on the problem
·
Locate and hire a professional survey company to conduct the survey. This survey may be
administered by one or more forms of communication (mail, email or phone), depending
on cost and anticipated effectiveness
·
Interpret results,
determine whether the problem requires
action, and produce
a report that explains the results
and implications for the Code
·
Develop a scope of work for the 2014-2015 fiscal year,
if warranted
·
A report providing technical information on the problem background, results
and implications to the Code submitted to the Program
Manager by June 15, 2014
·
A proposed
scope of work for 2014-2015 funding cycle, if warranted
·
A breakdown
of the number of hours or partial hours, in increments of fifteen (15) minutes,
of work performed and a brief description of the work performed. The Contractor
agrees to provide any additional documentation requested by the Department to satisfy audit requirements
5.1. Literature review
A review of relevant literature was conducted
to inform the project regarding scope, evidence, standards, and related
studies. The reviewed literature includes:
·
A position
statement (NRCA)
·
A letter
to the DBPR from the County of Palm Beach
·
ASTM and
TAS standards,
·
Peer
reviewed journal articles on modeling the corrosivity
of the coastal atmosphere (Mikhailov et al., 2004; Slamova et al. 2012),
·
A FRSA
article that helped motivate the study that is the subject of the report (Zehnal, 2013),
·
A NIST
Interagency Report that describes a study that was conducted to
determine the extent of metallic roof fastener corrosion (Rossiter et al. 1989).
The NRCA position statement (1986) and the Rossiter et
al. study (1989) are summarized here.
In
1986, the National Roofing Contractors Association (NRCA) released a bulletin
stating their position on fastener corrosion. Their concerns were shared by the
Asphalt Roofing Manufactures Association (ARMA), The Roof Insulation committee
of the Thermal Insulation Manufacturers Association (RIC/TIMA) and the
Single-Ply Roofing Institute (SPRI). The NRCA was concerned particularly about
the corrosion resistance of galvanized steel screws, and the associated risk of
loss of roof securement. The bulletin proposes that only long term corrosion
resistant fasteners be used for both new roof and reroofing construction
projects. These concerns parallel those raised by Zehnal
(2013), that data on the extent of corrosion is still hard to come by, the
cases referenced are largely anecdotal as they were 25 years ago, and
galvanized steel fasteners are still at the forefront of the corrosion
discussion.
Rossiter
et al. (1989) is a report that was commissioned by the U.S. Department of
Commerce in February, 1989. The study
was conducted to determine the extent of metallic roof fastener corrosion and
provide a future course of action. Data on the extent of corrosion was
determined to be lacking and the majority of information was anecdotal. To
compensate for the lack available data, the study was conducted via
questionnaire distributed to roofing contractors and inspectors. Of the sent
questionnaires, 45 were returned. In total, 1300 roofs were inspected, 15% of
which exhibited fastener corrosion. It was determined that the main cause for
corrosion was moisture and corrosion was predominantly found present in zinc
coated carbon steel fasteners. Moving forward, the study suggests that testing
of fasteners needs to account for chloride exposure and abrasion resistance (at
the time of the study, a sulfur dioxide/water vapor test was used), in-service
fasteners should be monitored regularly, and non-destructive monitoring
technology should be developed to record the condition of inaccessible
fasteners.
5.2. Interaction with Survey
Company
UF has been in
discussions with the Coordinator of Programming & Research for the University of Florida Survey Research Center (www.bebr.ufl.edu/survey), within the
Bureau of Economic and Business Research. Based on his extensive experience
with the development and execution of surveys, he recommended the following:
·
The performance period and size of the subject
(i.e. survey taker) database for this project indicates that the survey should
be conducted by phone call rather than email or standard mail. The response
rate for mailing surveys is lower, and takes more time than phone calls. A statistically
significant number of completed surveys is unlikely to be accomplished by mail
in the given time frame
·
400 is a suitable target for the number of
completed surveys. This will provide a confidence interval (sampling error)
that is small enough to justify conclusions regarding code modifications or the
initiation of a phase two project in the next fiscal year
·
The budget set aside for the survey company is a
critical factor with respect to a number of critical and related factors such
as: number of questions in the survey, number of call-backs to a subject before
they are removed from the contact list, number of surveys that can be completed
·
The budget set aside for the survey company
necessitates that UF take the lead in the identification of survey subjects,
and their contact information. UF will provide the survey company with a
complete list of survey subjects and their contact information. This is
described in Section 5.3
This contact has
agreed to provide UF with a proposal containing options with a tiered fee
structure. This will provide the information necessary to decide the optimal
survey approach by balancing the various tradeoffs within the available budget.
For example, more completed surveys, more call-backs per survey taker, more
questions in the survey, all require resources. Upon receipt of this tiered
proposal, UF will present the optimal methodology and the survey questions to
the Roofing TAC for comment.
5.3. Construction of survey
subject database
A database needs to be constructed containing
the names and contact information (business name and phone number) for the
survey subjects. The survey subjects will be licensed roofing contractors,
inspectors and building officials. It was determined that the survey company
cannot provide the database construction service within the budget cap.
UF has been creating this database by pursuing
multiple data sources. Information is available online from the Florida
Roofing Sheet Metal and Air Condition Contractors Association (FRSMACA) and the
National Roofing Contractors Association (NRCA). DBPR also hosts public data
records at www.myfloridalicense.com,
which provided licensed and certified contractors of all categories. A data
request was filed with DBPR to attain name and contact information for building
officials. UF combined and refined these four data sources to isolate only
roofing related professionals, and filter out repeat entries.
The
complete database consists of 6500 potential survey subjects. 4000 of these
entries include a contact phone number. At the suggestion of the Florida Survey
Research Center, UF contacted MSG Genesys, a firm
that provides a number-matching service. If it is determined that the Florida Survey
Research Center (Section 5.2) will attempt more than 4000 contacts within their
budget, UF will contract with MSG Genesys to provide
a numbers match and complete the 6500 contact database.
5.4. Development of survey
questions
This task is awaiting the budget tiered proposal
from the Florida Survey Research Center (Section 5.2). With a fixed budget there
is a tradeoff between number of completed surveys and number of questions in
the survey. The construction of the survey subject database (Section 5.3) provides
the total number of survey subjects, and provides a realistic cap on the
potential number of completed surveys (a high-end estimate is 20% call /
completion success rate). UF expects to know by March 24 how narrowly focused
the survey needs to be. A draft will be created and submitted to the Roofing
TAC for comment.
ASTM designation: B117 11. Standard
practice for operating salt spray (fog) apparatus.
ASTM designation: D610 08. Standard practice for
evaluating degree of rusting on painted steel surfaces.
ASTM designation: F1136/F1136M 11. Standard
specification for zinc/aluminum corrosion protective coatings for fasteners.
Building Code Advisory Board of Palm Beach
(2012). Letter to the DBPR regarding observations of corrosion of metal
roofing fasteners
Mikhailov, A., Tidblad, J. and Kucera,
V. (2004). The classification system of ISO 9223
standard and the dose-response functions assessing the corrosivity
of outdoor atmospheres, Protection of Metals, 40(6) 541-550.
National Roofing Contractors Association
(1986). ARMA-NRCA-RIC/TIMA-SPRI position on rusting
and corrosion of fasteners in roofing assemblies, Technical Developments
Bulletin #14.
Rossiter, W., Streicher,
M. and Roberts, W. (1989). Roofs: a review of
available information and identification of research needs, NIST Interagency Report
(NISTIR 88-4008).
Slamova, K., Glaser, R., Schill, C., Wiesmeier,
S. and Kohl, M. (2012). Mapping
atmospheric corrosion in coastal regions: methods and results, Journal of
Photonics for Energy, Vol. 2.
Testing Application Standard (TAS) No. 114-95. Test procedures for roof system assemblies in the high-velocity hurricane
zone jurisdiction. Appendix E. Test procedure for corrosion resistance of
fasteners, batten bars and stress distribution plates.
Zehnal, M. (2013). How widespread is roofing
fastener corrosion in Florida? Roofing Florida Magazine, a publication of the
FRSA
None at this stage
