August 2011 Archives

I opened the door to enter the office building lobby. The sound was loud and unmistakable - an electrical transformer humming away, loudly. Following the sound I found the room about 20 feet away with the door propped open to help ventilate the transformer.

The photo shows a simple steel louver in the door for ventilation, too. Obviously it was not enough to keep the temperature of the electrical room within perceived acceptable limits. The door may have been propped thinking lower temperature would help reduce the humming. For power transformers, the hum is mechanical in nature caused by the core laminations when magnetized. Time and increased temperature can weaken the laminations causing the hum to increase. Additional cooling will not reverse lamination damage, nor reduce the hum.

The humming and temperature were not the only difficulty with this room. The hollow metal door and frame are both fire rated. The rating is unknown because the labels were painted over. And the louver in the door was not a fire rated louver. So the fire rating of the exit access corridor is compromised by this electrical room door, even without being propped open.

The International Building Code (IBC) references NFPA 80 (2007) - Standard for Fire Rated Doors and Other Opening Protectives as the standard for fire rated doors. In the 2007 edition of NFPA 80, annual fire door inspection was added to the standard.

This door is the poster child for why annual inspections are necessary.

Is marine grade plywood specially treated to resist salt water environments or severe exterior exposure?  NO.  Okay then what is marine grade plywood and why would it be used?

Marine grade plywood is a special grade of softwood veneer core plywood as defined by APA - The Engineered Wood Association and Voluntary Standard PS 1 "Structural Plywood." the standard is available as a free download from APA after registering.

Marine grade plywood must meet all the requirements for Exterior plywood plus the following: 

1. Only Douglas-fir and Western Larch plies without knotholes are permitted in the plywood construction.
   
2. The panels are available with sanded A-A, A-B, B-B faces or HDO and MDO faces, only.
   
3. The standard limits repairs in Grade A faces to a maximum of 9 in a 4 x 8 foot panel.
   
4. Inner plies to be minimum Grade B.
   
5. Crossband gaps and edge splits and end splits and gaps are limited by dimension and number.

So there you have it. No special preservative, no special adhesive. Merely limits on the veneers. If decay is a concern, even marine grade panels should be preservative treated.

Other EXTERIOR plywood may contain plies of other species, Grade C plies that do contain knotholes, and larger gaps in the plywood core.

For years the concept of metal gages confused me:

• Why was it that the thicker the metal the smaller the gage number - seems counter intuitive?

• Why was it that the same gage was a different thickness for different metals (i.e. why was 12 gage steel sheet thicker than 12 gage sheet aluminum)?

• Why was it that the same gage was a different dimension for sheet and wire made of the same metal?

A few years ago I decided to look it up, and it turns out it has to do with how metal sheets and wire are produced.

Metal sheets are pressed between a set of rollers and metal wires are drawn or pulled through a series of dyes.  Each dye or set of rollers reduces the thickness of the metal by a certain amount.  The gage indicates how many dyes or sets of rollers the metal has passed through, e.g. 12 gage means that the thickness of the metal has been reduced 12 times from its initial thickness.

The amount of thickness by which the metal is reduced in each step depends on:

• The tensile strength and malleability of the metal at a given temperature.

• The shape of the final product. (A sheet has more area over which to spread tensile loads than wire.)

• The original thickness of stock from which the sheets or wires were created.

If the dyes or rollers tried to reduce the thickness too much in one step, the metal would tear apart under the stress.  If dyes or rollers reduced the thickness too little, the process is inefficient and costs more to produce.

The standards for each metal developed independently since the producers of each metal were also independent of each other, i.e. steel manufacturers were not producing aluminum and setting the thickness standards for aluminum goods, the aluminum manufacturers were doing that.

That is why different metals and metal products have different thicknesses even though they had the same gage number.

Now that the metal industry as a whole (manufacturers of steel, copper, aluminum, etc.) has established actual measured thicknesses as the standard, the use of gages as a reference is completely passé.  However, you can now wow your friends at cocktail parties with your knowledge of how and why the system of gages was developed.

The metal framing industry stopped using imprecise gage thicknesses and started using precise minimum base metal thicknesses. Yet, many A/Es continue to specify metal framing by gage. Why adopt the newer standard? How did Underwriters Laboratories (UL) and Gypsum Association (GA) fire resistant designs incorporate the change?

Visit http://www.conspectusinc.com and click Tech Tips to view or download B2010 Metal Framing Thickness 11.08.01 and all previous Tech Tips.

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

 

Recently representatives of a very large company in the industry visited our office to pick our brains on the usual market research:  "How do you specify"? "What causes you to choose one product over another"? "What is the most important aspect of the product to you"? ...and so on. The message they took back with them was loud and clear from every specifier in attendance. What is most important to us? "Information". And what is the most important delivery method of that information? "Personal Service from the Product Rep". And what is the most important service the rep can provide?  "Call me back".

 

There it is, plain and simple- "Call me back". When we call a product rep it is usually because something was dumped on us last minute, we need quick, accurate information, and the product website is not helpful. Manufacturers could increase their market share if they all had "super reps". We all know a few...folks who get back to you quickly and can supply answers. Unfortunately, like anything else, not all reps are created equal. Here is a brief example.

 

On a recent project for a large architectural firm, who was working for a huge client, who was involved in multiple projects with this architect, a question of compatibility and warranty came up. Briefly, they needed to create a barrier floor in a high-rise to protect lower floors from leakage. Fine...there are many liquid-applied products available that will work. BUT...the client wants to use Product X because they've had success with it. Ok fine, BUT now they would like to install miscellaneous finish floor products over the barrier material, such as fully adhered carpet tile, VCT, ceramic tile, vinyl plank flooring, etc. Our client then asked for help in confirming that all of those materials would be compatible (in particular, the adhesives) and also if a warranty could be offered with such a system.

 

I called several people at the various finish product manufacturers who were helpful, but passed the liability issue off to the barrier product. I then contacted Product X and got a technical rep, who said, "Sure, no problem". He would check and get back to me. That later turned into, "Send me cut sheets from all of the adhesives and I'll pass them to our chemistry guys".  After a long wait the client moved ahead with the preferred product because the Owner insisted. More than a month later, I had forgotten about the situation when our Architect called and inquired if I had received any answers. For the sake of brevity, the conversation went on and on, with my pointing out to the rep that this customer has been and still is using a LOT of his product, and it would be prudent to get the testing done to ensure that continued use.  Well, a few weeks later the crickets are chirping, and I still don't have the information.

 

Subsequently I have spoken to representatives of other similar product lines who have told me that they could certainly supply the documentation associated with such a request, and coordinate with the other manufacturers to offer a warranty. They also offered to have the testing done to support such a warranty if needed. That is great, but the client has moved ahead with Product X, evidently with no assurances. I can think of one manufacturer that would lose a prominent customer if it were up to the specifier.

 

As specifiers we do a lot of research and we can find answers. When we can't find the answer, however, the product rep is the most important thing between us and the sale of a product.

So your project has a vegetative roof. Will it be insured under Factory Mutual? If so did you know you will need to comply with FM 1-35.   Do not get confused and think this has to do with wind uplift.   FM 1-35 provides general guidelines for green roof systems.

Here is the link to download the free data sheets produced by FM Global.  You must register first: http://www.fmglobal.com/fmglobalregistration/

Here are some things we see on vegetative green roof projects that are not known, missed, or misunderstood for vegetative roofs.

• Including the Electric Field Vector Mapping (EFVM) with the vegetative roof should be enough to comply with FM right?
• Sure including EFVM is a great on detecting a leak early before there is a major issue but the EFVM is not even mentioned in FM 1-35.   FM 1-35 states you need to perform a flood test prior to installing anything above the membrane.  The test includes a standing water leak test of the entire vegetative roof with no less than 2 inches of water, blocking all scuppers and downspouts for 24 hours.  The membrane seams are walked before and after the water is drained. If there are signs of leaks test cuts are made according to the membrane manufacturer and then patched per the membrane manufacturer. The flood test will be repeated until no leaks are detected.
• Including and installing the EFVM is the same for all membrane roofing.
• No - We have found that some manufacturers require that the grounding screen for the EFVM is installed under a cover board because their membrane will not adhere to the grounding screen.   This location is a concern because if you get a leak in the membrane the water can travel over the surface of the board and show the leak in a different location.   There are some manufacturers that include the grounding screen under the membrane which we believe is the correct location.

With the above mentioned items be sure to:

• Specify a flood test if your project is under FM 1-35 and understand all other requirements within FM 1-35 for the vegetative roof assembly. 
• If you will include the EFVM show the correct location of the EFVM materials on your drawings and/or list the correct install location in the specification for the selected membrane. Lastly don't forget to ask the question "So where did you say the grounding screen goes".

The CSI Specifying Practice Group met to discuss editing master specifications for construction projects. Listen to the recoded session or view the presentation below.



To understand how to edit the master specs, be sure to know how these specs are developed. Each master spec is written to be nearly all things, to nearly all specifiers, for nearly every project. So why "nearly?" Well, it is impossible for master spec writers to conceive every possible scenario and include it in the masters. They do attempt to capture about 80 percent of what may be required for most construction projects. Master specs try to be inclusive. Project specs result from judicious deletion and thoughtful addition.

Masters are written to accommodate varying degrees of project complexity and different methods of specifying. A single spec document will be the starting point for writing a two story wood framed townhouse and a 800,000 sf state of the art medical facility. Not all the requirements in the master should reasonably apply to both projects. And if the specifier chooses to use a proprietary instead of performance specifying method, most of Part 2 of the spec could be eliminated.

The scale, quality, and approach to writing specs differ for every project. These differences are responsible for the major pitfall in using master specifications: If in Doubt - Take It Out. Excesses in specifications will add unnecessary costs and may injure your reputation, especially when the excess becomes apparent by a busted budget.

Excessive testing, submittals, meetings, and mockups are commonly specified by not removing a master requirement. After all, it is master written by highly qualified specifiers, so it must be appropriate to include. Well, not always. Remember scale. Including a mockup for a material with a small installed quantity will greatly inflate the cost of the material.

Deciding what to retain or delete from a master spec can be decided more easily by editing the product information in Part 2 first. Once the products are defined, then the administrative and execution requirements in Part 1 and Part 3 can be tailored to fit the products. Editing the spec beginning in Part 1, may result in more excesses, just because the scope of the section will not be understood until Part 2 is completed.

To specify products, determine what is important to the project. Just because a product has specific performance, it may not be relevant to the project. Acoustic ceiling panels may be selected for light reflectance and surface texture, without consideration of the acoustic properties. Just because the master spec lists noise reduction coefficient (NRC) for the ceiling panel, does not mean it must be specified.

Carefully consider those delegated design requirements that are passed along to the contractor. When specifying standard products, designed and tested for a purpose and supported by published test data, delegated design is probably not required. Storefront for example is usually installed within a defined opening that is designed by the architect or engineer.

Manufacturers typically publish span and load tables for storefront, so designers can select the appropriate system for the project. Delegated design should not be required. Master specs include delegated design requirements for virtually every exterior envelope component. Be careful to remove delegated design when not required.

When using a proprietary method to specify products, then descriptions, performance, and reference standards may be deleted. However, some description other then the model number and manufacturer's name may be necessary if alternative products will be considered. There must be enough information to base a decision for accepting alternative products.

With all the great conversation, there was no time to review the Part 1 and Part 3 considerations or the ways to adapt a master to a design practice. This discussion topic will be continued at the September meeting.  See http://www.conspectusinc.com/blog/2011/09/editing-master-specifications---part-2.html for Part 2.

Join the group and listen to the finale to this session.

Is it the Architect or the Specifier? The best I can tell, it depends.

It depends on when the selection is made.
It depends on whether more than one selection must be made.
It depends on what the product is.
It depends on the individuals making the selections.

Here are my thoughts on the subject. But I would like to hear yours.

We find that when required product selections become surprises or are delayed until the decision can no longer wait, the Specifier will make the decision. This seems to be because the Architect is fully engaged in completing drawings for a scheduled issue. His time is consumed in coordination and cannot be diverted to material selections.

The surprises are often caused by owners changing their minds, unexpectedly. This puts the Architect into a frenzied scramble to adjust weeks or months of work in a short time that was planned for other activities. There is little hope of controlling owner's decisions. Indecision is caused by many circumstances, but mostly inadequate information or little experience with a product type. Information and experience are controllable, given adequate time to address the issue.

For specifications requiring more than one product and manufacturer, often the Specifier makes the selections other than the basis of design. The Architects rely on the Specifier's experience with many products to know what will match the basis of design. This is a reasonable assumption when the product is a commodity item. If the product is custom or required to perform specialized functions, the Specifier may not be able to select alternative products, unless he was intimately involved in selecting the basis of design.

If a product is selected for its visual appearance, only the Architect is capable of determining what other products will be acceptable. Often there is but one that can offer the desired color, texture, and pattern. And that is the one the Architect selected as the basis of design. The Architect must make the decision. For aesthetic products, researching exact matching alternative products is a foolhardy waste of time.

When the manufacturer doesn't matter, don't make a product selection. Specify by reference standard or by description without naming a product. There is no rule that a manufacturer and product must be named.

Purely from my own observation of many individuals on many projects, the more creative the individual, the less likely a product selection. Why? Because design is never done. And the chance to find a better solution at a future time must always be available. Specifiers will make more decisions when working with creative people because someone must for the spec to be completed.

Now, off to decide the products to us on the next projects...

I took this photo at a prospective client's office building when visiting for the first time. Even when I saw this in person, it took some pondering to decide its use. So what do you think?  What is this?  Add your guess as a comment below...

We have a winner: Randy Dial on behalf of Door Hardware Institute.  It is a door stop to protect sprinkler piping. Here is the photo of the surroundings.