EXPRESS FILMS EXPERT QUIZ #1 - OCTOBER 2011

EWF · October 20, 2011

We are very appreciative to TD & the community for providing a sub forum for Express Window Films. We want to do all we can to make this an educational area for all. In furtherance of this objective, we will be posting educational/recreational quizzes here from time to time.

Our first quiz deals with Solar Performance Parameters:

Total Solar Transmittance

Total Solar Reflectance

Total Solar Absorbtance

Visible Light Transmission

Visible Light Reflectance (Int)

Visible Light Reflectance (Ext)

Infra-Red Rejected

Winter Median U Value

Shading Coefficient

UV Rejected

Emissivity

Solar Heat Gain Coefficient

Total Solar Energy Rejected

Luminous Efficacy

Solar Heat Reduction

Glare Reduction

Many of you who deal with flat glass films know these well. Others find them rather confusing. Did you know that there are several constant ratios and other mathematical relationships that exist amongst these numbers? How many can you cite?

Whomever can cite the most complete (and first) list wins a 50-Pack of Olfas, courtesy of EWF!!

Also - if anyone has a suggestion for a future quiz, please email me at howard@buytint.com

Good luck!! Let the posted answers begin !!!!!

-Howard / EWF

vquestfilms.com · October 20, 2011

Nice quiz Howard!

EWF · October 21, 2011

Thanks Vq !!!!

72 views and no takers yet. I will post the answers on Friday 10/28, before I leave for SEMA. Hopefully somebody claims the Olfas !!

(You probably already have a few of them in stock) !!!!!

Coming to SEMA, Vq ??? Come and see me at GLOBAL. We are planning a practical demonstration on how window films are made from scratch.

Howard

TomTint · October 21, 2011

Howard for mathematical equations do you mean something as simple as TSR TST and TSA will always equal 100%

EWF · October 21, 2011

Howard for mathematical equations do you mean something as simple as TSR TST and TSA will always equal 100%

That's the first one !!! !!! TSEr+TSEt+TSEa = 100%

Right now, the Olfas are yours.

-Howard

Edit = syntax

vquestfilms.com · October 21, 2011

Thanks Vq !!!!

72 views and no takers yet. I will post the answers on Friday 10/28, before I leave for SEMA. Hopefully somebody claims the Olfas !!

(You probably already have a few of them in stock) !!!!!

Coming to SEMA, Vq ??? Come and see me at GLOBAL. We are planning a practical demonstration on how window films are made from scratch.

Howard

:lol I'll let someone else play., I've got a few OLFA's... I am looking forward to the equational answer for IR rejection. :nope

I'll stop by on Tuesday.

EWF · October 21, 2011

I am looking forward to the equational answer for IR rejection.

Hi Vq,

I don't believe there is one. Most of the major lines (Llumar, Vista, Panorama, Solar-Gard, Madico, Hanita) are now following IWFA and NFRC guidelines and have stopped reporting it, in favor of SHGC/SC. The major holdouts are 3M & Huper and they show no sign of yielding.

Reference: http://www.filmnow.com/MACRO_FILES/IWFA_IR.pdf

See ya Tuesday !!!

-Howard

vquestfilms.com · October 22, 2011

I am looking forward to the equational answer for IR rejection.

Hi Vq,

I don't believe there is one. Most of the major lines (Llumar, Vista, Panorama, Solar-Gard, Madico, Hanita) are now following IWFA and NFRC guidelines and have stopped reporting it, in favor of SHGC/SC. The major holdouts are 3M & Huper and they show no sign of yielding.

Reference: http://www.filmnow.c...LES/IWFA_IR.pdf

See ya Tuesday !!!

-Howard

Howard,

Try referencing Llumar Air 80, they advertise IR rejection. Vkool would be another. Strangely, I found IR rejection numbers for EWF films too. What range are your reporting your IR rejection? http://www.filmnow.c...Specs%20Web.htm

Here is an interesting fact about Southwall. Did you know they were they second MFG to get both Huper and Vkool films NFRC certified? They would have to follow NFRC guidelines to do this.

Have a safe trip out to Vegas.

EWF · October 22, 2011

Hi Vq,

As usual, you ask excellent questions. People have come to expect square answers from me, so here you go. Your question is one that I had anticipated.

You will note in my post that I mentioned the manufacturers that have removed the IR Data: Llumar, Vista, Panorama, Solar-Gard, Madico, Hanita. Several others (including EWF) are in various stages of withdrawing or "deemphasizing" it. By way of example, Sun-Tek only publishes IR data on 4 of the 25 films listed in their data tables. Another example is Johnson, who only publishes it on just 3 of 32.

EWF’s next published update is set to occur on or before 11/7/2011 and all (100%) of the IR data is being removed. In doing so, we will be neither the first nor probably the last to do so. Like the others, we felt it was necessary to include IR data, so we would not be summarily disqualified from bidding on some significant projects. At this point in time, however, the tables have turned dramatically. Thanks in large part to the IWFA and the AIMCAL Window Film Committee, knowledgeable installers, consumers and specification writers are finally dismissing IR Data (in the USA) on an increasing basis.

The time has come and EWF can remove the IR data with less concern over disqualification. If and when it does come up, we can explain the omission by presenting the letter from the IWFA/AIMCAL Window Film Committee. You raise the issue of NFRC Guidelines. I call your attention to the fact that the NFRC does not now nor did they ever publish IR performance data. That should give you some idea as to their assessment of its usefulness.

Let me go one step further.

If you read the IWFA letter I referenced, it outlines the fact that IR is confusing/misleading and that SC/SHGC exists as a much more accurate & comprehensive measure of solar performance (their exact words). Let me provide more insight and detail into why this is so.

“IR Rejection” like all other “rejection” measurements are taken from the outside surface and measure the energy coming off the glazing and toward the meter. Unless the client told you that they want a film that will heat the air outside their building, rejection data by itself, while not entirely useless, is not where you want to focus. What matters is what is going on inside, not outside.

“Rejection” is made up of 2 components. The first is the energy that is directly reflected away. The second component is the energy that is absorbed by the glazing and re-radiated outward. Rejection tells you nothing about the energy which is absorbed by the glazing and reradiated inward. This is why SC/SHGC exists. It takes into account the energy that is directly transmitted PLUS the amount that is absorbed by the glazing and radiated inward. Because Ceramics absorb more than other films (at similar VLTs) this increased absorption also increases the amount that is reradiated inward (decreasing overall performance) . That’s why you need to focus on SC/SHGC.

You see the rather strong language (confusing and misleading) used in the IWFA’s memorandum on this subject. Do clients really care how much you are heating the air outside their building? Of course not. They care how much they are being “shaded” from the solar energy, which includes the energy absorbed by the glass and radiated inward. Only the SC/SHGC tells you that.

The problem for the “holdouts” is that when evaluated in terms of SC/SHGC the premium selling prices for these films are not justified. Applying the SC/SHGC metric (as suggested by the IWFA/AIMCAL Window Film Committee) and in light of the NFRC’s complete omission of IR Data, the perceived “performance edge” suggested by the IR Rejection leads people to spend more and get less.

Our IR data is at 1025nm. I have not seen the AIR80 data you refer to, but that product is quite popular in Asia where (unlike the USA) IR data is common so I am not surprised. Rest assured, the Asians will figure it out one day as well, just as we have in the USA. Vkool is also very popular in Asia, so it’s not surprising that they are still including it.

-Howard