Cross Laminated Timber specification?

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Author Message David G. Axt, CCS, CSI ,SCIP Senior Member Username: david_axt Post Number: 1780 Registered: 03-2002 Posted on Friday, April 26, 2019 - 01:57 pm:    I have a project that has cross-laminated timber (CLT) framing. Any advice would be appreciated. David G. Axt, CCS, CSI, SCIP Specifications Consultant Axt Consulting LLC Jeffrey Wilson CSI CCS SCIP Senior Member Username: wilsonconsulting Post Number: 285 Registered: 03-2006 Posted on Friday, April 26, 2019 - 06:24 pm:    When I did some research on mass timber construction (including a tour of several buildings in Portland) OFRI was a great resource (Oregon Forest Products Institute). My contact was Timm Locke, Director of Forest Products. I don't know whether they have spec info, but they are the experts in these materials and their applications. Jeffrey Wilson CCS CSI SCIP Wilson Consulting Inc Ardmore PA Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 877 Registered: 10-2007 Posted on Friday, April 26, 2019 - 10:47 pm:    Have you considered asking the engineer specifying the product? Michael Chusid, RA FCSI CCS Senior Member Username: michael_chusid Post Number: 482 Registered: 10-2003 Posted on Monday, April 29, 2019 - 05:02 pm:    My article about CLT and lightning protection systems can be read at http://bit.ly/HeavyTimber-LPS. Key Finding: When lightning hits a tree, the tree can burn from the inside out. Same with CLT or other heavy timber. It is prudent to conduct the lightning risk assessment required by NFPA 780. See bit.ly/LightningRisk. Michael Chusid, RA FCSI CCS 1-818-219-4937 www.chusid.com www.buildingproduct.guru Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 879 Registered: 10-2007 Posted on Tuesday, April 30, 2019 - 03:07 pm:    I would like to understand why it is not appropriate to ask the engineer specifying CLT to provide a specification for that product? Similarly I am surprised that the electrical engineer is not involved in specifying the lightening protection system. Please explain why the electrical engineer should not be involved with writing the lightening protection specification. John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1779 Registered: 03-2002 Posted on Tuesday, April 30, 2019 - 03:40 pm:    Mark, it may be partly regional expectations. In the past, I had experiences with electrical engineers not being willing to do lightening protection. Similarly, some structural engineers wanted me to write wood framing sections that they would comment on. I thought that strange, but there it was. Existing wood framing or timber framing sections in MasterSpec seem to me that they could be relatively easily modified to include cross-laminated timber. Michael Chusid, RA FCSI CCS Senior Member Username: michael_chusid Post Number: 483 Registered: 10-2003 Posted on Tuesday, April 30, 2019 - 04:15 pm:    First, full disclosure. I am a consultant to a firm in the lightning protection system (LPS) industry. (This means I am available as a (hopefully)"trusted advisor" and to make educational presentations to your office or professional society. Contact me at michael@chusid.com.) 1. There is nothing wrong with the EE being involved in specifying LPS. If an architect is the prime consultant to an owner, however, it is the architect's responsibility to advise the owner on whether or not the building should have lps. If the decision is in favor of LPS, the prime designer can specify the system or delegate specification to another party. 2. There are only a few jurisdictions in which LPS or a lightning risk assessment is required by code. Where it is required, it is not included in electrical codes like NFPA 70. So the owner, or prime consultant, has to make the determination. 3. While lightning does involve the flow of electrons, an LPS is not like the power systems that are included in electrical engineering. The current is measured in hundreds of thousands of amps and millions of volts. Few EEs or electrical contractors are trained or qualified to design or install LPS. The most respected qualification is certification by the Lightning Protection Institute (LPI). 4. LPS is part of the building enclosure that protects the building from meteorological conditions. You wouldn't put gutters and downspouts in Division 22 - Plumbing just because water flows through them. 5. Determining if LPS is indicated can be determined by NFPA 780 risk assessment. An assessment can be done in 15 minutes using program at https://ecle.biz/lightning-risk-assessment-guide/. 6. Specifying LPS is straight forward. Quality and performance are determined by specifying LPI, NFPA, and UL standards. Design can be delegated to an LPI certified professionals. Installation should be by an LPI certified installer. and Commissioning to the LPI-Inspection Program (an independent 3rd body). A non-proprietary guide specification is at http://www.constructionspecifier.com/wp-content/uploads/2015/08/264100-LightningProtection-guidespec.doc. 7. The key word in LPS is "System". It is not just air terminals on the roof with conductors to ground electrodes. To create prevent current from jumping from the LPS system to other building components, it can require bonds to rooftop equipment, structural system, plumbing, HVAC, other metal bodies, services entering through building perimeter, site equipment, process equipment, other grounding systems, etc. In my opinion, it is a mistake to have LPS in Division 26 - Electrical. For many decades, it was included in Division 13 along with other types of Integrated Construction and Facility Protection. I have proposed a reversion to Div. 13 to MasterFormat. Finally, I invite you to read my article on "The Architect's Standard of Care" at https://ecle.biz/wp-content/uploads/2015/01/Lightning-Protection.pdf or my other articles at https://ecle.biz/ecle-resource-center/articles-newsletters/. Mark, as a Structural Engineer, you may be especially interested in the article from Modern Steel Construction. Thank you for letting me share one of my passions. Michael Chusid, RA FCSI CCS 1-818-219-4937 www.chusid.com www.buildingproduct.guru Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 880 Registered: 10-2007 Posted on Tuesday, April 30, 2019 - 04:34 pm:    Even if you are modifying an existing specification for CLT the engineer specifying the product should be involved. That is not reflected in previous postings which suggest that it could be resolved by specification writers acting alone. The lack of involvement of engineers in writing technical specifications is a result of the fact that engineers are not knowledgeable about specifications. This is a failing of CSI. Another contributor is the practice of specification writers , instead of expecting the engineer to provide specification sections, providing the engineer with a master to edit. This send the message that the engineer should play a passive role in writing the specification sections and discourages the engineer from taking ownership of the technical specifications. Even if the electrical engineer does not design the lightening protection system the electrical engineer should be involved in coordinating this section. I suspect that it is not desirable to connect the lighting protection system to the electrical system ground as implied by the article provided. Just because a member of the design team is not contributing to the production of specifications does not mean that it is appropriate for the specification writer to specify those systems. Why does CLT create a concern regarding lighting strikes. Why is this concern only applicable to heavy timber and not to conventional wood framing? I see no reason why a lighting strike could not ignite conventional wood framing. Michael Chusid, RA FCSI CCS Senior Member Username: michael_chusid Post Number: 484 Registered: 10-2003 Posted on Tuesday, April 30, 2019 - 05:09 pm:    "Why does CLT create a concern regarding lighting strikes." The type of structural system does not effect propensity for lightning strikes, but the type of damage that can occur changes. While the CTL industry is doing a good job exploring the consequences of fires that originate outside of structural members, it has not addressed the hazard of fire due to lightning. "Why is this concern only applicable to heavy timber and not to conventional wood framing?" Lightning risk assessments should be conducted regardless of the structural material used as the potential for damage, injury, and death due to lightning is not limited to fire. Michael Chusid, RA FCSI CCS 1-818-219-4937 www.chusid.com www.buildingproduct.guru Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 881 Registered: 10-2007 Posted on Tuesday, April 30, 2019 - 06:23 pm:    As a structural engineer I would discourage the use of the steel frame as part of the lighting protection system. The connection of the lighting protection system to the steel frame has the potential to cause problems due to welding of holes being made to the steel frame. Some regions of the buildings lateral system are considered protected zones and would preclude these connections. Is the welding processes used for electrical connections consistent with the AWS structural welding codes? Poor non-structural welds can cause problems for the structural performance. Connections of the electrical or lighting protection systems to the structural system should be coordinated with the structural engineer. When steel members are connected using bolts there are real concerns regarding what is the electrical resistance of thee connections that may be more than assumed. These connections were not designed to be good electrical connections. Do you know what is the electrical resistance of these structural connections? The multiple grounds being proposed for lighting protection systems have the potential of creating ground loop currents which can cause problems with some electrical equipment. You must involve the electrical engineer. David G. Axt, CCS, CSI ,SCIP Senior Member Username: david_axt Post Number: 1781 Registered: 03-2002 Posted on Tuesday, April 30, 2019 - 06:28 pm:    In my neck of the woods it is pretty common for architectural specifiers to write the structural sections (CIP concrete, rough carpentry, sheathing, glulam, structural steel, steel joists, steel deck, cold formed metal studs, etc.) with input of the structural engineer. Most of my Part 2 just says to refer to Structural Drawings (or Structural General Notes). Structural engineers or more concerned with structural characteristics that LEED documentation, primer application, concrete sealers, etc. A few structural engineers (poorly) write their own specifications. Yes I agree that CSI should bring them up to speed. I do not mind writing structural sections though I am slowly changing my opinion. David G. Axt, CCS, CSI, SCIP Specifications Consultant Axt Consulting LLC Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 882 Registered: 10-2007 Posted on Tuesday, April 30, 2019 - 06:57 pm:    I have enough experience with structural specifications and general notes to know that it is not feasible to address all relevant issues in General Notes. In addition General Notes on drawings are almost without exception a disorganized collection of various issues. The biggest problem for the engineer when writing specifications for a project is the formatting of the pages to match the architects unique criteria. Why must each architect have unique formatting requirements? A commonly overlooked problem is the specifying of the code required special inspections. In general the code is not explicit regarding the nature of the special inspections. Michael Chusid, RA FCSI CCS Senior Member Username: michael_chusid Post Number: 486 Registered: 10-2003 Posted on Tuesday, April 30, 2019 - 10:12 pm:    Mark, Great questions. Here is what I know. There are very few connections and they are mostly at the very top or bottom of the structural frame. The welding technique is exothermic welding with a small charge of thermite. See https://en.wikipedia.org/wiki/Exothermic_welding. I am not aware of an AWS standard for it. It makes an excellent, corrosion resistant connection between copper cable and structural steel. If necessary, welds can be excluded from protected zones. More frequently, the cable to steel joint is made with bolts (3/8" dia or less, so not very big compared to structural bolts) or clamp-on connectors. The connections between structural members do not require special treatment. The powerful current in lightning will jump through any gaps or paint. Structural steel is only allowed to be used as conductors if it is not less than 3/16" thick. To your point about ground loop circuits and noise in the power supply, right again. There does have to be coordination between the LPS and EE designers and installers. I would like to learn more about your perspective from an structural point of view. Call me at 818 219 4937 (Los Angeles) or suggest a time by writing michael@chusid.com. Michael Chusid, RA FCSI CCS 1-818-219-4937 www.chusid.com www.buildingproduct.guru Jerome J. Lazar, CCS, CSI Senior Member Username: lazarcitec Post Number: 2011 Registered: 05-2003 Posted on Tuesday, April 30, 2019 - 10:58 pm:    David, on many of my apartment and mixed use projects I prepare the Structural specs pro bono, I require the PE to review the sections, provide comments, and take temporary ownership for the one job only. The PE must confirm acceptance via email. This works 90% of the time and maintains a uniform project manual. Sorry Mark, some PE's have bigger egos than Architects, they think they can write specs, I wind up getting dissertations from them that no one wants to read. Michael Chusid, RA FCSI CCS Senior Member Username: michael_chusid Post Number: 487 Registered: 10-2003 Posted on Wednesday, May 01, 2019 - 12:42 am:    These photos show welded, bolted, and clamp-on connections between conductor cables and structural steel used as conductors. In each of these photos, the cable connects to the grounding electrodes. At the top of the structure, similar connections will lead to through structure penetration devices leading to the rooftop. Michael Chusid, RA FCSI CCS 1-818-219-4937 www.chusid.com www.buildingproduct.guru Guest (Unregistered Guest) Unregistered guest Posted on Thursday, May 02, 2019 - 01:07 pm:    I've always required the structural engineers write their own sections. They seem to manage alright without me doing their work for them. Whether it is CSI's failing or not is beside the point. David, I'd argue the structural engineers you're working with are not meeting their standard of care. I've worked with plenty in Seattle that write their own specifications without any push back. As for the formatting and why architects all have different requirements ... do you complain that you have to use different titleblocks on your drawings too? What is the difference? Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 883 Registered: 10-2007 Posted on Thursday, May 02, 2019 - 01:33 pm:    While a different title block can be accommodated with minimal effort the reality is that dealing with formatting can consume many hours. Sometimes this can be delegated to the office administrative personnel but all too often it sucks up time of the project engineer. Not every office has a Microsoft Word zen master. The worse and admittedly extreme situation was where the architect required that the files be in word perfect format with all of the control characters removed. Consider the problems you would face if required to conform to a clients formatting requirements and then think how bad it would be if you had not mastered all of the features of your word processing system. The CSI Page Format could serve as an effective standard. What is the problem of adopting an industry standard. Michael Chusid, RA FCSI CCS Senior Member Username: michael_chusid Post Number: 491 Registered: 10-2003 Posted on Thursday, May 02, 2019 - 01:40 pm:    It's been a while since I wrote a project manual, but recall that there was plenty that had to be written in a structural framing section that required "architectural" consideration: - types and locations of shop-applied priming. - corrosion resistance considerations. - quality of exposed to view surfaces. - Part 1 administrative requirements. I wonder: if the structural engineer writes the steel or structural concrete spec sections, how often does the architect and architectural specifier read the engineer's section for coordination? Michael Chusid, RA FCSI CCS 1-818-219-4937 www.chusid.com www.buildingproduct.guru Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 884 Registered: 10-2007 Posted on Thursday, May 02, 2019 - 02:21 pm:    In my experience the Architect rarely coordinates with the structural specifications. If Part 1 administrative requirements are provided at the start they should not present problems. Painting requirements may be best addressed in a parallel painting specification section. The architect needs to take the lead. If the extent of shop painting is to vary it will need to be shown on the drawings. Instead of having one highly integrated specification section that addresses structural and sophisticated painting requirements I believe it is typically best to create two parallel specification sections that reference each other. Architecturally exposed steel is another area that requires considerable architectural involvement. Often the architect decides to punt because of cost implications and I suspect the amount of time to coordinate. AISC has some good resources on this subject. Guest (Unregistered Guest) Unregistered guest Posted on Thursday, May 02, 2019 - 05:01 pm:    The problem with simply adopting PageFormat is that while it is a good guide, it still leaves a lot open for variation. Additional information needs to be communicated with the intent to follow PageFormat as stated in the publication itself. Even simple things like whether Article numbering uses 1 or 2 digits after the decimal (i.e. 1.2 or 1.02), or whether the Article title should be bold or not, is not dictated by PageFormat. Not to mention page margins, font style, font size, etc. All those options and acceptable variations mean that one architect's PageFormat compliant instructions will likely vary with another architect's PageFormat compliant instructions. If you are finding a lot of time being wasted trying to adapt your offices sections to match the formatting requirements of your clients, I can only suggest you look into ways to minimize that time wasted. Setting up and using paragraph styles, for example, would allow you to change the font, size, and style of text fairly quickly with a variety of software tools out there. P.s. The architect requiring WordPerfect files will get no sympathy from me. I have guesses as to why they did that, and I wouldn't agree with any of them. I would have pushed back on the requirement. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 885 Registered: 10-2007 Posted on Sunday, May 05, 2019 - 01:46 pm:    Regarding Page Format, when I look at the printed example it seems to me that a number of those options are resolved. In any case why not issue a revised Page Format that resolves these issues? I have expended considerable time using paragraph styles and while powerful I find them to be sensitive to use. While a full time specification writer may develop total mastery of this tool this level of mastery does not usually exist in the office of a consultant. I have looked at a number of how to books and have yet to find one that really explains how to use paragraph styles. So what may be natural for a specification writer may not be realistic for other mortals. Walk a mile in the shoes of others. The use of WordPerfect was not so much driven by the architect but was driven by the long time secretary who I suspect only knew how to do things one way. Is it easier for the architect to confront and possibly replace the secretary or is it easier to inconvenience the architect’s consultants. The message in consulting firms is to accommodate not confront the architect and because the principle does not involved in the day to day production work the consultants principle does not feel the pain and is less likely to back staff. Guest (Unregistered Guest) Unregistered guest Posted on Tuesday, May 07, 2019 - 12:40 pm:    Mark, I can't say I understand where you see those options as resolved in PageFormat. Perhaps the printed example you are looking at is simply an example of one possible variation. The following are excerpts from the text of PageFormat (Third Printing - September 2013): Article Format: "Articles are addressed by a number consisting of the Part number, a decimal point, and one or two digits starting with either 1 or 01. ... To further improve navigation, Article titles may be in bold font." Note that bold font is not a requirement, but rather a suggestion to improve navigation. Typesetting and Fonts: "PageFormat does not specify a specific font style or size." Page Margins: "The bound edge margin should range from 13 mm to 20 mm (0.5 inch to 0.8 inch) ... the unbound edge margin should range from 13 mm to 20 mm (0.5 inch to 0.8 inch), and top and bottom margins should range from 10 mm (0.4 inch), to not more than 20 mm (0.8 inch).