March 2011 Archives

This term cropped up recently on a set of shop drawings.  I was asked by the Project Architect if truss head screws are the same as the counter-sunk, flat head screws that had been specified.

The simple answer:  No.

A truss head screw has a head with flat underside and a slightly domed top.  It has almost no exposed edge.  The head may be designed for any number of different turning devices from flat bladed and phillips screw drives to allen wrenches and Torx drives.  Truss head screws can be designed for use in metal, wood, or other materials.

See the following for a wide selection of different truss head screws: 

http://www.mrgusa.com/pdfs/144-145truss.pdf

Wikipedia defines a truss head screw as: Lower-profile dome designed to prevent tampering.

http://en.wikipedia.org/wiki/Screw

Warning:  If your employer restricts access to certain web sites, you may not be allowed access to this site.  However, the site is legitimate and suitable for children.  See your IT department, if necessary, to manually remove this site from the restricted list.

Because there is almost no edge to the head, it is true that you couldn't use a wrench or a pair of pliers to remove a truss head screw, but that hardly makes them tamper resistant.  Do not specify this type of screw as a tamper resistant screw without also specifying that a special device is required to remove it.

The MyWord.info web site has a definition that is far too vague and broad to be useful.  However, they also give the following list of other terms that might be used to mean "Truss Head Screw:

• oval binding bolt
• oval binding head bolt
• oval binding head screw
• oval binding screw
• oven bolt
• oven head bolt
• oven head screw
• oven screw
• stove bolt
• stove head bolt
• stove head screw
• stove screw
• truss bolt
• truss head bolt
• truss head screw
• truss screw

Must damaged fireproofing be repaired or will limited damage be permitted in the completed construction? Construction operations often damage fire protection products installed at the start of a project. Spray-on fireproofing is installed immediately after the structural steel is erected. Then the fireproofing is removed to install hangers needed for ductwork, piping, conduits, ceilings, and countless other products.

Researching this question for an architect, I could not find anything from Underwriters Laboratories (UL) that permits any acceptable percentage of missing fireproofing. So, I contacted our trusted W. R. Grace Monokote product representative, Michael Giardinelli, CSI, CCPR, to confirm what is permitted. He reported that no code or standard allows the integrity of spray fireproofing to be relaxed.

According to Michael installers typically order additional material to patch damage caused by other trades. The patches are installed by spray or by hand to repair the damage, depending on the size of the patch. The damaged fireproofing must be repaired to comply with the fire resistive design assembly.

AIA's MasterSpec® and ARCOM's SPECTEXT® master specification systems both recognize the need to inspect and repair fireproofing damaged by other trades. By these specification systems, the contractor is responsible for inspecting and repairing the fireproofing to ensure its integrity. Otherwise the exposed portion of the steel can quickly transfer a fire's heat through the member, potentially causing premature structural failure during a fire.

Be sure to specify inspection and repair. Then enforce the requirement to ensure the structure will protect both the occupants and the firefighters during a fire.

Combustible construction can provide perfect paths through concealed spaces to allow fires to spread quickly and undetected. Fireblocking and draftstopping combine to minimize these perfect paths to help protect the property and the occupants. Learn about the dangers of continuous concealed spaces exemplified by common cockloft fires.

Visit http://www.conspectusinc.com and click Tech Tips to view or download B1010 Fireblocking and Draftstopping 11.03.01 and all previous Tech Tips.

Share your comments, your opinions, about this month's Tech Tips, by posting a comment, here.

When referring to a set of alphanumeric characters used in building signage, the term "font" is commonly misused.  Here is the correct definition of the word "font:"  The following definition comes from http://www.webopedia.com/TERM/f/font.html.  

Font:  A design for a set of characters. A font is the combination of typeface and other qualities, such as size, pitch, and spacing. For example, Times Roman is a typeface that defines the shape of each character. Within Times Roman, however, there are many fonts to choose from -- different sizes, italic, bold, and so on. (The term font is often used incorrectly as a synonym for typeface.)

Therefore:

Times New Roman is a typeface.

Times New Roman, bold, 10 point is a font.

Times New Roman, bold, 14 point is a different font than Times New Roman, bold, 10 point.

Helvetica is a typeface.

Helvetica, bold, 10 point is a font.

Helvetica, italic, 10 point is a different font than Helvetica, bold, 10 point.

Using the terms "font" and "typeface" correctly will help ensure that the intent of your drawings and specifications are clearly understood.

The International Building Code (IBC) Section 1009.4.4 requires stair risers and tread widths to be uniform height and width within a tolerance of 3/8 inch throughout the entire flight of stairs. Why is this important? The reason became instantly apparent the first time I climbed these egress stairs in a 1912 hotel as the most convenient path between meeting rooms on adjacent floors.

Uniform risers and tread widths allow people to use stairs without concentrating on their gait. The first few steps set the pattern, that once recognized is easily repeated until the exit is reached. Uniformity can help speed descending stairs in an emergency. Changing the pattern may cause people to lose their balance, trip, and potentially fall.

Fortunately, I was climbing, so I was able to catch myself as I nearly fell from the drastic change in riser height. The typical riser is about 6 inches high. The greatest riser is more than 8 inches and the least about 3 inches. The minimum riser is 4 inches by IBC Section 1009.4.2.  Climbing, the riser sequence is 6 - 8 - 3 - 6 while making the turn at the intermediate landing. After the first time, I learned. So did others. We did not avoid the stairs, but the travel was cautious and deliberate. Every time I was on the stair with others, reminders were abundant.

Now imagine an emergency, without normal lighting, and an assembly occupancy floor trying to use these stairs. A single trip-and-fall would cause exiting chaos and probably severe injuries.

The majority of this month's more than 50 CSI Specifying Practice Group members was specifiers that have used manufacturer's specifications to create construction specifications. The discussion was lively and caused the meeting to run overtime before reaching the mid point of the planned presentation. And debate continued by email after the group meeting ended and may continue here by leaving a comment to this posting.

So next month's meeting will continue the discussion, and conclude, perhaps. Be sure to join us April 7 for Part the Second. Join the group, now, to share your thoughts.

Louis Medcalf and I invited Phil Kabza, SpecGuy, to help present this month's topic. Phil is a specifier who routinely writes manufacturer's specifications. This is a perspective that many specifiers do not have. So we gladly welcomed this alternative viewpoint.

The group polls confirmed what we believed to be true. The majority use manufacturer's guide specs:

• Frequently
• As information for writing spec sections from scratch
• Never as written without major editing
• And are compelled to add competing products

Since the group majority was specifiers, this may not represent the industry as a whole. It is believed that architects and engineers that are not dedicated specifiers are more likely to use manufacturer's specifications as written or with some modifications to suit a project's conditions.

Manufacturers have mixed purposes for their specifications. Other than getting their product specified, they tend to establish limitations for liability, competition, and responsibility. Retaining these limits in a project spec can have adverse effects on the project. The most troubling may be inadvertent exclusion of work from the contract when the spec requires work to be "by others" or defines work that is not included.

Formatting can give an instant clue to the age of manufacturer's specifications. Most manufacturers have not adopted the latest SectionFormat, published in 2008. Some still exist using MasterFormat 1995, 5-digit, 16-division numbers and titles. This format was replaced in 2004. Of course nothing has changed since 2004, like codes and standards, so just changing the number and title may only give the illusion the information is current.

Manufacturer's specs will rarely be well coordinated with the other specifications, especially Division 01 - General Requirements. Before using manufacturer's specs for a project, they should be coordinated with Division 01 and drawing terminology. Editing decisions must be made and product options must be selected to suit the project conditions.

Phil reviewed what manufacturers include in Part 2 - Products of the specifications. The most contentious: the competition. Most manufacturers do not want to name their competition in their own spec. The perception seems to be that naming competitors may keep them from getting the work. The poll showed most specifiers will add competitors if they are not named. For a manufacturer's spec, it seems logical that the manufacturer should want to control the competition, naming only products that create fair competition. If the competition is not named, the manufacturers give up control to the specifier, and the result may not be fair.

The group asked about "gotcha" clauses. Of course, the classic gotcha is the single requirement that makes the spec proprietary. It is often difficult to recognize gotcha clauses because they are subtle and innocuous. Test standards with specific results, minimum dimensions, and minimum performance can make specs proprietary if not compared with the competition. Avoid gotcha clauses by asking the named competitors to review the spec. Every good product rep has seen the manufacturer's spec before and knows the pitfalls.

What questions do you have that should be discussed in Part the Second? Post your questions here to to share with the Group.

On March 1, 2011 ARCOM and The Construction Sciences Research Foundation (CSRF) announced that ARCOM acquired SPECTEXT® from CSRF. Read the full announcement at http://www.arcomnet.com/spectext.php.

SPECTEXT® is a commercial master guide specification system used by architects, engineers, and others to write construction project specifications. Conspectus has maintained and developed SPECTEXT® for CSRF, continuously, since 1998, taking over that responsibility from the National Institute of Building Sciences. Conspectus has written new sections and updated the entire collection of architectural and engineering specifications to keep SPECTEXT® current with the construction industry trends, codes, and reference standards. Conspectus also developed advanced editing tools, EDITSPEC, for CSRF to automate many repetitive specification editing tasks.