ASTM E1105 Spray Racks and Testing

[construction2010]

thread507-222919

I ran across this old forum where someone was searching for an ASTM E1105 spray rack and wanted to leave this tid-bit I discovered recently while searching the internet. I found a company online at

http://www.ftltesting.com

that manufactures spray racks that conform to the ASTM E1105 standard. What I liked about this company as opposed to what else I found out there was that they are also capable of "calibrating" the racks to the test standard because they are an independent accredited testing lab.

 

[Ron]

That's fine that you want to buy from a group that can "calibrate" the spray rack...that really only works for the first calibration. It is not cost effective to send a spray rack back to the "factory" to get it calibrated every 6 months.

We build our own spray racks and calibrate them. The calibration procedure is not that difficult and as long as you have traceable weighing and measuring devices, the calibration is valid. Further, we do in-place field flow and pressure checks on projects to check the on-site conditions, using a calibrated flow meter and pressure gauge.

Spray racks are easy to build, routinely get broken during testing and must be checked when rebuilt. We have found that it is much easier and less expensive to do that ourselves. We have built spray racks from copper, PVC, CPVC and even stainless steel. There are advantages and disadvantages to each. Personally, I like copper.

 

[construction2010]

Yeah, the copper racks are really great. Some of our guys are pretty rough with the racks so they last a little longer, but PVC is easy to repair in the field and much easier to move around. I prefer PVC for myself, but Copper for some of my work crews.

We used to do our own calibrations and make our own racks because it seemed easy enough and we thought we'd save some money, but the more I looked at it I wasn't saving anything. I'd have to have my guys waste company time making racks and repairing them when I could have them at a jobsite and it took them longer than I wanted. My time is money after all, and definitely more so than the couple of hundred for repair and re-calibration anyway!

But what really pushed me to stop all in house calibrations and rack making were the beatings we were taking during mediations, depos, and trials. I'm still green to the consulting game and those sneaky lawyers know how to sway opinions and question the integrity and credibility of the racks we were using for testing. We lost some trial cases due to stuff like that and figured it best to just use the services of a company who specialized in that sort of thing.

I'll let you know how it turns with them out since I just placed my order on Saturday and my new racks should be ready for pick-up some time next week. They also gave me some great price discounts since I was new and wanted to be set up on a regular schedule. So far, they've been pretty helpful and even offered some free training courses on quality control testing at their lab that I'm probably going to send my guys to when we have some free time, but we're staying busy right now which is good and why I needed some racks ASAP. You don't happen to have any history on the ASTM E1105 by any chance do you, like the original authors of the standard and their qualifications?

 

[Ron]

construction2010....ASTM E1105 was first published in 2000. It is under the jurisdiction of Committee E06 on building performance, and in particular subcommittee E06.51 on performance of windows and doors.

As with all ASTM standards, the document was committee developed, with no single author getting credit. The committees and subcommittees are made up of a cross section of the industry, with window and door manufacturers, engineers, contractors, academics, and other interest parties being committee and subcommittee members.

Each proposed standard goes through a rather rigorous review by the subcommittee members until it is voted to become a standard. That process can sometimes take several years.

I'm very familiar with the process used by lawyers in mediation, deposition and trial. My group specializes in construction forensics, so we deal with it routinely. One "mistake" I've seen other experts make is to overstate the importance and accuracy of some test methods. They then get trapped by attorneys into defending their own practices when that's often just a "red herring" compared to the real issues of the test. Remember, this and other tests are intended to create and replicate a "standard" condition, not necessarily one that routinely exists in reality. While the standard should be followed as closely as practicable, it is sometimes necessary to deviate from the standard to accommodate local conditions. When you do this, just document what you did and your justification for such.

As for the calibration of a spray rack, it makes little difference whether you are putting out 5 gph/sf or 8 gph/sf...the key is to get full coverage at a reasonable spray rate. Further, the standard requires running the test at the calibration flow and pressure, which is sometimes not possible, so field calibration has to be done to comply with the standard.

Perhaps more important is the vacuum system and manometer used to measure the differential pressure. We use precision manometers and have them calibrated annually, at least.

 

[construction2010]

Thanks for the pointers, I will keep those things in mind from here on out!