AC257-1007-R3
McIntyre Associates, Inc.
8565 E. Grandview Lake Dr.
Walls, MS 38680-9422
www.mcintyre-inc.com
32
Mike H. Freeman
7421 Hunters Tree Cove
Memphis, TN 38125
http://members.aol.com/wooddoc
Tuesday, September 25, 2007
Mr. Michael O'Reardon, P.E., CBO
Senior Staff Engineer
ICC Evaluation Service, Inc.
900 Montclair Rd, Suite A
Birmingham, AL 35213
Subject: Acceptance Criteria AC257-1007-R3 – Oct. 2007 Mtg. Agenda Item No. 32
Dear Michael:
We would like to offer a few written comments for consideration to the ICC-ES
Evaluation Committee regarding AC257-1007-R3, Proposed Revisions to the
Acceptance Criteria for Corrosion-Resistant Fasteners [to be retitled, CorrosionResistant Fasteners and Evaluation of Corrosion Effects of Wood Treatment Chemicals],
prior to the scheduled October 12th Evaluation Committee hearing. The comments
below focus on the sections of AC257 that relate directly to the evaluation of corrosion
effects of wood treatment chemicals.
We feel that AC 257 in its current form should not be adopted by the ICC-ES and the
approving committee.
Although we applaud your work on this project, we feel that the work in ACTM
Committee G01.14 and their current balloted method should be further reviewed.
Additionally, we are not sure how the current version of AC 257 will fit directly into the
AC326 acceptance cities should it pass at the upcoming meeting.
The AC 257 Task Force has met three times, and still has major disagreement within the
Task Force regarding AC257.
If possible, we would like to hold a joint AC 257 and AC 326 Meeting in Birmingham at
the earliest possible convenience were we might possibly be able to iron out the issues,
which relate to both AC326 and AC257, and their interactions. Additionally, we do feel
that visual ratings are not the best way to monitor corrosion results, and the structural
integrity of a treated wood fastener or fastener system. I would propose a full day Task
Force meeting, with the first half spent on AC257, and the remaining day on AC326.
Finally, we would ask that if AC257 does pass at the upcoming meeting, which we
believe is a improper thing to occur, we would ask that the Effective Date of AC 257 be
held in abeyance for at least 12 months, or it be held for further study, based on the
newly adopted E12 method in AWPA and the outcome of the Go01.14 and G01
Committee ballots in ASTM.
If we may clarify the above, feel free to contact us via e-mail, phone, or fax.
Respectfully submitted,
Mike H. Freeman
Independent Wood Scientist
Memphis, TN
Craig R. McIntyre, PhD
McIntyre and Assoc.
Walls, MS
2
AC257-1007-R3
Osmose®
32
Osmose, Inc., 980 Ellicott Street, Buffalo, NY 14209-2398 716-882-5905 Fax: 716-319-3130
September 25, 2007
Mr. Michael O'Reardon, P.E.
Senior Staff Engineer
ICC Evaluation Service, Inc.
900 Montclair Rd, Suite A
Birmingham, AL 35213
Subject: Acceptance Criteria AC257-1007-R3 – Agenda Item No. 32
Dear Mr. O'Reardon:
We would like to offer several written comments for consideration to the ICC-ES Evaluation
Committee regarding AC257-1007-R3, Proposed Revisions to the Acceptance Criteria for
Corrosion-Resistant Fasteners [to be retitled, Corrosion-Resistant Fasteners and Evaluation of
Corrosion Effects of Wood Treatment Chemicals], prior to the scheduled October 12th Evaluation
Committee hearing. The comments below focus on the sections of AC257 that relate directly to
the evaluation of corrosion effects of wood treatment chemicals.
It is our belief that no one has experience testing metal coupons in contact with treated wood,
as assembled in accordance AWPA E12, using the ASTM B117 test protocol. Therefore, we
have no history or previous experience with this test protocol that would give us any confidence
as to its viability or appropriateness in establishing the relative corrosion characteristics of
proprietary wood preservative systems. It is also our understanding that there exist very few
test labs or individuals in the industry that posses a test chamber capable of performing ASTM
B117. The financial burden to acquire such equipment and develop the appropriate test
parameters would be prohibitive for third party contractors (accredited by IAS for this specific
testing) and sponsors. This appears to be a very similar situation to that where consideration
was given to using the draft AWPA/ISANTA protocol for fastener corrosion testing until it was
established that no one had any experience performing the protocol as written.
Furthermore, based on discussions at the November 2006 AC257 Task Group meeting, it
appears that the inclusion of ASTM B117 for evaluation of the corrosion effects of wood
treatment chemicals was done in an effort to incorporate liquid water into the test matrix in order
to simulate rain fall events that would exist in real world exposure conditions. The difficulty in
introducing water in the form of a bath, fog or spray into an accelerated corrosion test that
incorporates wood as a test substrate is really twofold. First, in order to generate reliable and
repeatable corrosion data, the wood test samples would have to uniformly adsorb and transfer
moisture and ultimately equilibrate at similar moisture contents. Achieving uniform moisture
adsorption and transfer within the wood test specimens is further complicated when the water is
introduced in a cyclic fashion (i.e. multiple wet-dry cycles). Secondly, introducing liquid water
into an elevated temperature and humidity environment may produce corrosion mechanisms
between the test metal and treated wood that are not characteristic of those experienced in real
AC257-1007-R3
32
world applications. Therefore, we would recommend to the committee to remove the
requirement for ASTM B117 for "Wet-Use" conditions.
As a member of the AC257 Task Group, it is a bit perplexing that a visual evaluation of
corrosion has been included in AC257, and even more perplexing that it is now the sole
evaluation criteria for performance. From active participation on the Task Group through
meeting attendance and communication with attendees when absent, there does not appear to
be a consensus that visual evaluation was to be weighed so heavily as conveyed by Chairman
Leichti. In fact, it was the consensus of both the ASTM G01.14 and AC257 Task Groups at the
November 2006 meetings in Atlanta that visual ratings should be excluded from metal corrosion
evaluations. A review of section 4.5.2 of AC257 shows that the base-metal weight loss and
changes in diameter are used as corrosion assessment criteria for fasteners with corrosionresistant mechanisms other than coatings. Given this precedent, it would seem logical that
weight loss could be established as an assessment criterion for uncoated coupons such as
steel, aluminum and copper.
To further support the above, it should be noted that many improvements have recently been
made to the referenced AWPA E12 coupon corrosion test standard by AWPA Subcommittee P6, of which you are a member. These improvements were a result of a consensus among many
wood preservation experts who have been directly involved with the corrosion characteristics of
treated wood for many years. This group continues to use weight loss (corrosion rate) to
establish the relative corrosiveness of candidate wood preservative systems. Based on the
above, we would recommend to the committee that the visual evaluation of corrosion be
removed as an assessment tool and weight loss determinations be used as the sole
assessment criteria for both fasteners and coupons.
We would further recommend to the committee that a detailed review of the newly revised
AWPA E12 Standard be conducted to reassess its appropriateness for evaluating the corrosion
effects of wood treatment chemicals. This standard has been used for many years with good
success, and given the latest revisions, should continue to provide valuable data.
If consensus can not be reached on the above suggested revisions, it is recommend to the
committee that the criteria presented in AC257 be put on further study to be revised by the
assigned task group.
Respectfully submitted,
Douglas J. Herdman
Assistant Manager, Applied Technology
Research Division
Osmose, Inc.
2
AC257-1007-R3
32
Michael O Reardon, P.E.
Senior Staff Engineer
ICC Evaluation Services, Inc.
900 Montclair Rd, Suite A
Birmingham, AL 35213
Email: [email protected]
September 24, 2007
RE: Comments on AC257, Proposed Revisions to the Acceptance Criteria for Corrosionresistant Fasteners and Evaluation of Corrosion Effects of Wood Preservatives
Dear Mr. O Reardon,
Upon review on the most recent draft of AC257, I have included some comments and
proposed revisions to the current acceptance criteria.
Section 3.1.8, line 179
This requirement precludes fasteners that are fully threaded or makes testing cumbersome
for fasteners that only have a very short section of shank length.
Section 3.1.9, line 183
the thickness of each coating layer shall be determined in accordance with the applicable
ASTM standards for coated fasteners
I don t believe this section can be left as such with no further direction. Which are the
applicable standards?
Section 3.2.4,
sampled and prepared following AWPA E12 isn t specific enough because that
standard has a specific wood sample size that is much smaller that what would be needed
for our test, especially fastener testing. A 2x4x6 block will be more appropriate for
coupon testing and 2x4x15 would be more suitable for fasteners because more screws can
be installed in a longer board.
Section 3.3.6, line 211
Change alloys to metals for consistency.
Section 4.1.5, line 238
Change randomly to alternately .
Section 4.1.5, line 245
This split criteria is pretty useless. I don t think we can expect to see a split that is wider
than the product that is creating the split.
Section 4.1.9
Actual wood properties shall be determined by a report from a third party lab to verify
retention levels, in particular.
This is important because with such a variable product, it s important know how close the
actual retention is the labeled product.
Section 4.2.2.2, line 342
Change Type VI to Type IV .
Section 4.2.4
Testing with coupon sizes mandated by AWPA E12 are 1 x 2 in which requires treated
wood samples that are ¾ x 1½ x 3 in. The coupon sizes are easy enough to acquire, but
wood samples of this size would need to be special ordered from a treater. If the purpose
is for manufactures to be able to get materials for testing, this is going to be difficult and
costly. I would recommend we change the wood sample size to something closer to 2 x 4
x 6 in and have metal coupons that are 2 x 3 in, which will be something testers can
acquire easily.
Section 4.2.7, line 285
Insert cleaning section similar to what is found in Section 4.1.7 for consistency.
The beginning and final moisture contents of the test members shall be determined by
using calibrated moisture meters in accordance with ASTM D 4444 or by oven-drying
methods in accordance with ASTM D 4442. For chemical treatments carried in water.
The initial moisture content of the test member shall not be less than 15 percent (ovendry basis), and for treatments applied dry, the test member shall be conditioned to
equilibrium moisture content at 90° F (32° C) and 90 percent relative humidity.
Section 4.4
Move the visual assessment section before the cleaning section (4.4.3). Assessment can
be done following the cleaning/weighing. There are many reasons why assessment should
be done before cleaning. It yields very meaningful results and for barrier coated screws, it
is possible to see where the barrier has been compromised through blistering. Once the
cleaning has been done, gathering that information will be impossible.
Section 4.4, line 348
Remove and Cleaning
Line 385
Insert cleaning section here
Insert Section 4.5.2.2
For each fastener, the form of corrosion shall be notes as general, pinpoint, or spots as
described in ASTM D610. Areas of compromise of top layer protection, such as
blistering or other adhesion problems shall be noted.
Section 4.5.4.2
Statistical methods still need to reference a known test standard. Some of the terms are
still confusing.
Section 4.3.1.1
If we are trying to determine the impact of treated wood on fasteners, what is the purpose
of testing screws in untreated wood?
Table 1, page 23
In Exposure Condition 2 for aboveground with coastal salt exposure, this should be
4.3.1.2, rather than 4.3.1.3.
4.3.1.1 (Exposure 1, Exposure 2 w/ Test Procedure 1 & 2) Comparing red rust on
benchmark fasteners to the percentage of red rust on alternate fasteners will likely be a
misleading exercise. The corrosion on HDG fasteners, is often zinc, which has to corrode
before the steel corrodes. However, with alternate fasteners, often the corrosion that
occurs is the base material and not the barrier, since that generally doesn t have any
metals in it. Zinc can protect the steel long after it has been consumed. Barrier coatings
cannot do the same. In fact, they may not be protecting the steel even when they are still
attached to the steel. But since the corrosion may be occurring under the top layer, one
might not even realize it.
When considering weight loss comparisons between benchmark and barrier protection
systems, it only makes sense to compare the weight loss of a tested screw that has been
stripped, due to the relative weight of the galvanized coating on the screws (which is
high) and the relative weight of the barrier coating on the screws (which is so small).
Thank you for consideration of these proposed revisions.
Sincerely,
AC257-1007-R3
Fastening Systems
Robert J. Leichti, Ph.D.
Sr. Compliance Engineer
Briggs Drive
East Greenwich, RI 02818
32
Tel 401-884 -2500
Fax 401-884-2485
Voice Mail X32166
[email protected]
September 18, 2007
Mr. Michael O’Reardon
ICC-Evaluation Service, Inc.
900 Montclair Road, Suite A
Birmingham, AL 35213
RE:
Comment on AC257-1007-R3
Dear Mr. O’Reardon;
The agenda items for the October Evaluation Committee meeting include AC257-1007R3. The revisions to AC257 are comprehensive, and they reflect a considerable effort
by the task group and ICC-ES to produce an acceptance criteria that addresses the
important corrosion issues. Please review the comments that follow as proposed
revisions to improve the acceptance criteria.
Line 35:
Action -- Delete the word “corrosion.”
…moisture or salt corrosion from coastal exposure. These fasteners….
Rationale – “Salt” is the corrosion accelerator but “salt corrosion” is not an accelerator.
Line 105 (Section 1.4.10)
Action – Revise to be a definition not instruction.
Sample Lot: A sample lot shall consist of at least 100 alternate of
benchmark fasteners that are representative of the population of
fasteners from which they are chosen.
Rationale – “Sample lot” is the item being defined, so it should not be part of the
definition. As a definition, this section should not be worded as an instruction.
Line 188:
Action – Upper case Southern Pine.
Rationale – Proper noun is a species group and is capitalized per ASTM D1165
(editorial).
Mr. Michael O’Reardon – AC257 Comments
September 18, 2007
Page 1 of 3
Line 214:
AC257-1007-R3
Action – Following Staff request, modify the coupon specification to a range of material
thickness.
….copper (ASTM B 370). Coupons of 16 gauge [54 mils, 0.0538 in. (1.37
mm)] are recommended although coupons of thickness ranging from and
including 14 gauge [0.0747 inch (1.90 mm)] to 20 gauge [0.0396 inch
(1.00 mm)] shall be permitted as alternatives.
Rationale – Test method sensitivity to coupon thickness is unknown, but results are not
expected to be affected over the range as proposed.
Lines 251-258 (Section 4.1.7):
Actions – (1) Address staff request for calibration of ASTM D4444 to D4442 and (2) add
tolerances to environment.
The beginning and final moisture contents of the test members shall be
determined by using calibrated moisture meters in accordance with ASTM
D 4444 or oven drying methods in accordance with D 4442. For chemical
treatments carried in water the initial moisture content of the test member
shall not be less than 15 percent (oven-dry basis), and for treatments
applied dry, the test member shall be conditioned to equilibrium moisture
content at not less than 90 ºF (32 ºF) and 90 percent relative humidity.
Rationale – (1) No additional wording is proposed to address the Staff comment for
calibration of ASTM D4444 based on D4442 because ASTM D 4444 addresses
calibration of conductance meters (D4444, Section 5) and dielectric meters (D4444,
Section 8). In both instances the calibration uses D4442.
(2) The supplemental wording “not less than” (bold type) meets the need of the test
method and provides sufficient guidance for the test method.
Line 277:
Action – Change the word “corrosion” to “exposure.”
Testing shall include corrosion exposure of metal coupons by to treated
wood in….
Rationale – The testing end point might not produce corrosion, and with no corrosion,
one could infer that the test is void. The testing is an exposure of metal coupons to the
treated wood that may or may not generate observable corrosion.
Mr. Michael O’Reardon – AC257 Comments
September 18, 2007
Page 2 of 3
32
Line 282:
AC257-1007-R3
32
Action – Modify the sentence to make it a procedure of the exposure test.
…be evaluated exposed with the treatment chemical at the end of the
test.
Rationale – The instruction should be one for the exposure tests because this section is
procedures for exposure; procedures for evaluation are given in a later section.
Line 291:
Action – Add tolerance to the environmental condition statement.
The exposure condition shall be conducted at a steady state of not less
than 90 ºF (32 ºC) and 90 percent relative humidity.
Rationale – Tolerance for the conditions is needed and a statement of “not less than”
meets the needs of this procedure.
Line 310:
Action -- Revise two words to make them plural (editorial).
….heads of the benchmark fasteners and percentage ….
Rationale – Makes the wording consistent with intent.
Line 336:
Action – Add tolerance to the environmental condition statement.
….temperature environment of not less than 90 ºF (32 ºC) and …..
Rationale – Change from temperature statement to one that expresses temperature and
relative humidity, the environment, is needed and the inclusion of “not less than”
provides guidance for tolerance of the environmental control.
Figure 1, caption -- Delete author date and initials from last line of caption.
If you have any questions about my comments, please feel free to contact me.
Sincerely,
STANLEY FASTENING SYSTEMS, L.P.
[by e-mail]
Robert J. Leichti
Sr. Compliance Engineer
/rjl
Mr. Michael O’Reardon – AC257 Comments
September 18, 2007
Page 3 of 3
AC257-1007-R3
32
September 25, 2007
Michael O’Reardon, P.E.
Senior Staff Engineer
ICC Evaluation Service, Inc.
900 Montclair Road, Suite A
Birmingham, AL 35213
Re:
AC257-1007-R3, Proposed Revision to the Acceptance Criteria for Corrosion-resistant Fasteners
and Evaluation of Corrosion Effects of Wood Treatment Chemicals
Mr. O’Reardon:
USP Structural Connectors has reviewed the proposed revisions to AC257 and offer the changes shown
below to provide additional clarity.
1. Section 1.2.1: We suggest editorially rewording this section as follows to read more clearly.
“This criteria is used to evaluate the corrosion resistance of fasteners
exposed directly to wood treatment chemicals and may be exposed to
one or more environmental corrosion accelerators (high humidity,
elevated temperatures, direct weather or high moisture, or salt corrosion
from coastal exposure). Applications in the scope of this criteria include:
1. Wood-to-wood connections
2. Metal-to-wood connections
3. Wood to other engineered materials connections
These fasteners are alternates to fasteners with code-recognized protection systems and
include:
1. Nails and spikes with diameter of less than or equal to 1 3/8 inch (9.5 mm)
2. Staples
3. Screws with diameter of less than or equal to 3/8 inch (9.5 mm)].”
2. Section 3.1.7: Add “before insertion into the wood test specimens” after the word “fasteners”.
3. Section 3.2.6: In response to staff’s request for additional information from industry we suggest
replacing the last sentence with the language below.
“Coupons shall be 16 gauge with a minimum thickness of 0.0538 inches
(1.37 mm).”
4. Section 4.1.3: Replace the work “typical” with “the manufacturer’s” to provide additional clarity.
5. Section 4.1.7: Insert the following sentence at the beginning of the section:
“The moisture content of the wood test specimens shall be taken when
the test assemblies are placed in the chamber and when they are removed
from the chamber.
6. Section 4.2.7: Revise the sentence to read as follows:
“The moisture content of the wood test specimens shall be taken when
the test assemblies are placed in the chamber and when they are removed
from the chamber
7. Section 4.3.1.3: Editorially replace the comma in the first sentence with the word
“and”.
8. Section 4.4.3: We suggest adding additional language to permit the use of
alternate cleaning methods, provided it can be demonstrated the cleaning method
doesn’t result in weight loss to unexposed samples when cleaned. The cleaning
product Evapo-Rust with sonication does an excellent job of removing corrosion
byproducts without removing the base material for zinc galvanized steel coupons.
We propose adding a sentence to the end of the section which reads:
“Alternate cleaning methods or cleaning products are permitted provided
it can be demonstrated they do not adversely affect the test results.”
We thank you again for the opportunity to review this proposed acceptance criteria. If you have any
questions or need additional information please do not hesitate to contact us.
Sincerely,
Greg Greenlee, P.E.
Director of Engineering
AC257-1007-R3
32
ICC-ES Committee Hearing, October 2007; Weyerhaeuser Comments on AC257; Page 1 of 2
Market Support Engineering
September 25, 2007
Michael O’Reardon, P.E.
ICC Evaluation Service, Inc.
900 Montclair Road, Suite A
Birmingham, AL 35213
RE:
Proposed ACCEPTANCE CRITERIA FOR CORROSION-RESISTANT FASTENERS AND
EVALUATIONION OF CORROSION EFFECTS OF WOOD TREATMENT CHEMICALS – AC257
Dear Michael:
We have reviewed the latest draft proposal for AC257 and would appreciate if the committee would consider the
following comments (primarily editorial) developed by our staff chemical engineers. As readers, we do not
believe that this is a user-friendly document. Possible improvements include:
•
Throughout the document, it references AWPA Use Categories (e.g. line 198, 270, etc.). However, on
line 274 there is a reference to table 1, which then describes "exposure conditions" that do not directly
correlate to the AWPA Use Categories. We suggest the committee integrate the use of the AWPA use
categories throughout the document and eliminate the confusing dual references to exposure conditions
vs. AWPA Use Categories (mostly in table 1 and in section 4.3)
•
The organizational structure makes the report difficult to read, For example, it starts out with the
following pattern:
3.0-Test Material Required
3.1: Fastener Corrosion Resistance
3.2: Treatment Corrosion Effects
4.0 Test Methods & Performance Requirements
4.1: Corrosion Resistance of Fasteners
4.2: Corrosion Effects of Wood Treatment chemicals
•
Then it deviates from this pattern, making the report confusing to the reader to follow. Because there
are 2 different objectives of the AC (fastener evaluation and wood treatment evaluation), this
compounds the problem. Possible improvements include revisiting the numbering and organization of
sections 4.3 thru 5.0 to make it easier to read and follow, using the same organizational pattern of
sections 3.0 and 4.0.
Weyerhaeuser Technology Center, WTC 2B2
P.O. Box 9777, Federal Way, WA 98063-9777
Phone: (253) 924-6499 ; Fax: (253) 924-4239
E-mail: [email protected]
ICC-ES Committee Hearing, October 2007; Weyerhaeuser Comments on AC257; Page 2 of 2
3) Other issues
•
4.3 Exposure Conditions (which don't correlate to AWPA Use Categories)
•
4.4 Fastener & Coupon Removal and Cleaning (should be broken out in to the 2 different categories,
Fastener Corrosion, and Corrosion effects of Treatments)
•
Assessment of Fastener and Coupon Corrosion (should be broken out into the 2 categories for ease of
use/understanding)
•
Quality Control (should be broken out into the 2 categories for consistency)
We hope that you find this input to be constructive. Thank you and the ES Committee for your consideration of
our comments.
Sincerely,
David S. Gromala (sent via e-mail)
David S. Gromala, P.E.
Director of Codes & Product Acceptance
Weyerhaeuser Technology Center, WTC 2B2
P.O. Box 9777, Federal Way, WA 98063-9777
Phone: (253) 924-6499 ; Fax: (253) 924-4239
E-mail: [email protected]