Air Barrier Testing: Bigger is Better
In the world of whole building air barrier testing, bigger is in fact better. Larger buildings tend to perform much better, with significantly less air leakage measured per square foot of building envelope, when tested. Why is this … more money for construction materials, more experienced personnel, a better quality control program? While these are all possible and reasonable answers, the answer is actually much simpler. Bigger buildings test better due to a combination of their overall size and geometry. Let’s analyze why this is.
Naturally, any simple analysis must be underscored by a key assumption. In this case, we assume that air leakage primarily occurs at critical interfaces (floor-to-wall, wall-to-roof, etc.) within the building envelope. While uncontrolled air leakage could occur within the field of a roof, wall or floor, this “field leakage” is generally negligible compared to the air leakage at interfaces, and can be ignored. While this may seem like a rather bold assumption, in the 150-plus whole building air barrier tests we have performed over the past several years, the most common and significant areas of air leakage for a building of any size generally occurs at the building interfaces.
Another key point to keep in mind is that larger buildings typically exhibit greater air leakage values while still meeting established allowable leakage rates. Allowable leakage rates are usually a function of the building size itself – the United States Army Corps of Engineers (USACE) air barrier testing protocol, for example, states that the allowable leakage rate should not exceed 0.25 CFM/ft2 of building envelope. For example, a building with a 100,000 ft2 building envelope can have 25,000 CFM of air leakage and satisfy the USACE requirement, while a building with a 10,000 ft2 building envelope can only have 2,500 CFM of air leakage and satisfy the requirement.
As you may have already guessed, our assumption and key point described above work against each other. A bigger building has more interface length and is therefore potentially leakier, but the same bigger building also has a larger building envelope and thus is allowed to “leak more”. While we will not get bogged down in the mathematical relationship between building envelope area and interface length, we easily recognize that building envelope area increases more rapidly than interface length as building size increases. And since envelope increases more rapidly, the “leak more” effect outpaces the potential leakage, which results in better results for bigger buildings.
The Leap: Building Enclosure Commissioning…a LEED Prerequisite
By Matt Heron,M
.S., P.E., LEED® AP
Those who have worked within the U.S. Green Building Council’s LEED rating system are familiar with “credits” versus “prerequisites”. For those who are not, a quick primer: credits are sought; there are many to pick from and the more you successfully achieve, the higher the “score” (high is good). On the other hand prerequisites MUST be done for all projects.
Commissioning (simply put: making sure a building works right) has been a prerequisite since the first versions of the LEED rating system family. This process has generally applied to mechanical, controls, and electrical systems. In previous and current LEED rating systems, commissioning the building enclosure was relegated to the dark, scary world of the “Innovation in Design” credit. I suspect this was a seldom sought and poorly understood credit (although a Pie project recently received this credit!).
Enter LEED 2012, still in draft form and scheduled for release soon. The most recent draft released for public comment includes the building enclosure as a PREREQUISITE system to commission. This, my fellow high performance building aficionados, is a big Leap. Are building owners aware of the Leap? Do project delivery teams understand the implications of the Leap? Do Commissioning firms, most of which do not have in-house enclosure expertise, know who to reach out to?
Pie has been been “commissioning” the building enclosure (under the auspices of consulting and testing) for over 10 years. We understand the Leap. Want to learn more? Contact one of our building science experts at 303-552-0177.
By the Time I Got to Work…….
By Christina Childrey
By the time I got to work today, roughly 24 earthquakes had already occurred worldwide according to the U.S. Geological Survey (USGS). The USGS records national earthquakes of 2.5 magnitude or higher, and those that occur worldwide at 4.5 magnitude or higher.
Most can readily recall the 2011 earthquake in Japan and subsequent tsunami, the 2010 earthquake that crumbled Haiti, and also the 2004 earthquake and subsequent tsunami that devastated 14 countries to include Thailand. In January 2005, the death toll from the later earthquake alone was estimated at 286,000 and another 1.7 million were reported to have been displaced throughout South Asia and East Africa.
Even more shaking, is the fact that of the 16 largest earthquakes recorded (8.5 magnitude and higher) since 1900, five have occurred over the last decade!
Working at Pie Forensic Consultants gives you a different perspective on what I like to call “unnatural” disasters. When large catastrophic events such as earthquakes occur, the engineers at Pie Forensic Consultants are often called on to go weeks or even months with little sleep and endless reports on the devastation. The hundreds of photos bought back from the field lend a much broader view of an event than say, local or even world news reports.
If you’ve ever watched the show Sanford & Son, you will recall Fred Sanford was always talking about the “big one.” In the CAT world, who knows when the next big one will hit.
Think Like a Water Drop: Part 3
By Fred Pope, P.E., Senior Forensic Engineer
Case 3
A rental property owner wanted to save some money by setting the thermostat to 55-degrees in a vacant house. He had heard this was a generally safe temperature fora newer, well-insulated house. But the frugality went a little too far and he closed all of the upstairs bedroom doors and turned off the heat registers in the bedrooms (he did leave them on in the two baths). When the temperature sank to 12-degrees below with a stiff north wind, the supply water pipe to the shower in the outside wall froze, leading to a significant water loss.
Lesson 3 A thermostat can only measure the temperature at its location. The setting of 55-degrees might have been acceptable if the heat had been more uniformly distributed in the house. It is critical that all areas with water pipes, including inside walls, be above freezing.
Pie’s Catastrophe Response Team Handling Claims from Epic Utah Wind Storm
The National Weather Service is calling the recent Utah wind storm, ‘the strongest wind storm in the region in years.’ Pie was quick to mobilize and assist with claims for damaged homes and buildings.
At Pie, we understand your need to complete a claim investigation as accurately and efficiently as possible; particularly during, and following catastrophes. Whether it is damage due to environmental forces such as wind, water, hail, snow, tornado, etc.; safety assessments; repair recommendations; or any other claim, the engineers at Pie understand that both you and your client want a rapid resolution.
We Offer The Following CAT Services:
- Structural Damage Assessment
- Roof Damage
- Damage and Safety Assessments
- Repair Plans and Recommendations
- Fire Damage Observations
- Nationwide Response
- 24-7 Claims Assistance
- Rapid Report Turnaround
- Commercial Claims Assistance
For all your CAT claims, count on Pie’s proven experience, call 866-552-5246.
Pie for the Holidays!
With a name like Pie Forensic Consultants, and in the spirit of our holiday season, we couldn’t resist the temptation to express our gratitude to our wonderful clientele by hand-delivering fresh pies. It’s not only a great way to visit our clients in person, but also to spread holiday cheer to their entire staff! Happy holidays from Pie!
Leave a comment if you love Pie!
University of Arkansas has Chosen Pie for BECx Needs for New Football Center
Pie’s Minnesota office is excited to provide building enclosure commissioning services (BECx) on the new University of Arkansas Football Center.
Pie is working in conjunction with the commissioning agency, Comfort Systems USA (www.csusaenergyservices.com), on behalf of the Owner, to provide design review, preconstruction quality assurance, and performance testing services to the elaborate new football center.
The modernized center will feature a new locker room, team meeting rooms, athletic training room, equipment room, a student-athlete lounge and study area, coaches offices, a recruiting reception area and a football museum celebrating the tradition of Razorback football.
The football center is being designed by Populous Architecture (www.populous.com). To learn more about building enclosure commissioning, visit: http://buildingenclosurecommissioning.com/
Thanksgiving Day Safety Tips
Happy Thanksgiving from Pie Forensic Consultants!
Wishing you and yours a memorable and safe holiday. Please take a minute to read over the Thanksgiving Safety Tips below!
From The American Red Cross – Oregon Chapters
Thanksgiving Day has more than double the number of home cooking fires than an average day according to the U.S. Fire Administration. In fact, each year more than 4,000 fires occur on Thanksgiving Day.
To help prevent home fires this Thanksgiving, the Red Cross suggests the following tips:
- Keep potholders and food wrappers at least three feet away from heat sources while cooking
- Wear tighter fitting clothing with shorter sleeves when cooking
- Make sure all stoves, ovens, and ranges have been turned off when you leave the kitchen
- Set timers to keep track of turkeys and other food items that require extended cooking times
- Turn handles of pots and pans on the stove inward to avoid accidents
- Follow all manufacturer guidelines regarding the appropriate use of appliances
- After guests leave, designate a responsible adult to walk around the home making sure that all candles and smoking materials are extinguished
Even with the best preparation and precautions, accidents can happen. Thanksgiving is high time for cooking related burns. Minor burns can be treated easily if you remember to save the butter for the rolls and not a burn. For a superficial burn, cool the area by running it under cold water until the heat eases and then loosely cover the burn with a sterile dressing.
Another danger that can interrupt a good turkey dinner is choking. The most common cause of choking is talking while eating. If you feel as if food may be caught in your throat, never leave the room, stay where others can see you and help if your airway becomes blocked.
To help someone who is choking, remember “FIVE-and-FIVE Can Keep Them Alive.” First, ask the person if they are able to breathe and if you can help. Once you know the person is unable to cough, speak or breathe, have someone call 9-1-1 or your local emergency number, lean the person forward and give FIVE sharp back blows with the heel of your hand. If the obstruction isn’t dislodged, give the person FIVE quick, upward abdominal thrusts. If you are alone, you can perform abdominal thrusts on yourself, just as you would on someone else. Thrusts can also be administered by pressing your abdomen firmly against an object such as the back of a chair.
Just because we get to take a break from dieting on Thanksgiving, doesn’t mean we can throw caution to the autumn winds. Remember these suggestions and have a happy and safe holiday.
Murfreesboro Hail Storm
From The Daily News Journal (Murfreesboro, TN)
MURFREESBORO — Almost three weeks after an unseasonable October hail storm, the toll wrought by the five-minute deluge is still being tallied.
Insurance claims are still being filed, dozens of auto shops around town are busy banging out dents and local auto dealers are hawking hail damage specials.
Judy McCarthy with State Farm said that the insurance agency has received nearly 3,600 vehicle damage claims and more than 1,300 homeowners claims for the area. And it’s not done yet.
A State Farm-sponsored vehicle assessment station is open near Bumpus Harley Davidson on Northwest Broad Street, and will remain open until Friday. The agents have seen an average of 160 vehicles a day, according to officials with the insurance agency.
Toyota of Murfreesboro has reduced the price on hail-damaged vehicles, with 140 on the lot at the time the storm hit.
“Everything (on the lot) was affected,” said Adam White with , located at 2505 S. Church St. “We are selling our preowned as is, and the new vehicles we are repairing.”
Vehicles in their lot saw an average of $800 to $4,000 each in damages. White said many of the vehicles are selling at discounts averaging $3,000.
“The real benefit I see is for the people who are going to trade because they can take the hail damage check from their insurance and put it toward the trade with their vehicle, as long as it isn’t totaled,” White said.
Barry Tidwell, general sales manager for Nissan of Murfreesboro on Memorial Boulevard, estimated his inventory alone suffered close to $1 million in damages.
“We had 430 vehicles on the grounds,” he said. “We are going through and attempting to fix many of the vehicles.”
Approximately 40 percent will be repaired and many other certified pre-owned cars will be sold as-is or fixed and sold at discounted prices.
“They are selling. It’s an unfortunate thing to happen to the local people,” Tidwell said.
For those not looking to buy a new vehicle, filing a claim, getting their vehicle inspected and then getting it repaired can be frustrating, especially when many are having to wait weeks or even months to see the work done.
In need of catastrope support? Is a roof inspection scheduled?
Pie’s forensic engineers are experts in assesssing storm-related damage, and with staff located in Murfreesboro, TN, we can be of immediate assistance. Call Pie today at 866.552.5246.
