Help me understand these DP ratings, please

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dandidit
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Help me understand these DP ratings, please

#1 Post by dandidit » Thu May 24, 2012 6:38 am

Hello,
I'm shopping windows for a new house we are building. We (builders) will be installing the windows in my house. We are looking at:

Okna (although they don't call back)
soft-lite (the dealer didn't call back)
Paradigm (tons of communication with that dealer)
Simonton (good communication with that dealer)

I'm reviewing the DP specs (and other information) for the Paradigm windows and I was wondering if anyone could educate me on the difference between the "C" and "R" in the first column. I see it says that the "C" requires an optional "EP" upgrade. So, what does C and EP mean? And, what are your thoughts?

http://www.paradigmwindows.com/pdf/test ... ium_dh.pdf

If you're interested, I'm considering the Tripple RLE 7138/CLR/RLE 7138/Blend 8,10

I've got large windows (3' x 5'), mostly and they are coming in at $389 each. Similar Simontons (but lacking reinforced sash) are coming in around $498

Also, this spec sheet provided by Paradigm is awesome. Does anyone know if Simonton or the others have a similar sheet? The Simonton is the 5500 Reflections series with tripple HiPro glass package, 1/8", super spacer, ProSolar Low E, Krypton.

Thanks!

dandidit
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Joined: Tue May 22, 2012 1:04 pm

Re: Help me understand these DP ratings, please

#2 Post by dandidit » Thu May 24, 2012 6:45 am

OK, found some info for Simonton, but WOW, it is hard to parse... I cannot positively identify my window in this big pile of data... any tips?

http://www.simonton.com/TopMenu/Trade/T ... f?i=41&g=0
http://www.simonton.com/TopMenu/Trade/S ... a.pdf?i=41

dandidit
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Re: Help me understand these DP ratings, please

#3 Post by dandidit » Thu May 24, 2012 7:51 am

Alright, got some info on the Simonton - However, this doesn't tell me the air infiltration rate... I don't think. Thoughts?

36 1/8" (O) X 60 7/8" (O) 5500 Reflections White Double Hung; Rough Opening
Size; BOX; 1'' IGU Thickness; HiPro Glass Package; Super Spacer; ProSolar
Low E; Krypton Gas; Triple Glazed; Double Strength (1/8"); Full Screen
Fiberglass Extruded Screen Mold; 00 No Reinforcement; Two Air Latches;
Two White; Logo Lock; Head Expander; Sill Extender; Glass Warranty
(UI=97"); DP:25; Test Number=91631.01; U-Factor:.20; SHGC:.23; Unit qualifies
for ENERGY STAR® region(s): Northern, North Central, South Central, Souther

Oberon
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Re: Help me understand these DP ratings, please

#4 Post by Oberon » Thu May 24, 2012 4:20 pm

R means residential and C means commercial.

Are you looking for impact windows? What DP are you considering?

dandidit
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Re: Help me understand these DP ratings, please

#5 Post by dandidit » Fri May 25, 2012 6:37 am

Hi, I'm residential and we are in Upstate NY, so DP is not important. However, if it leads to better air infiltration rates, then it is somewhat important. I'm not sure if the two are directly related or not...

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HomeSealed
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Re: Help me understand these DP ratings, please

#6 Post by HomeSealed » Fri May 25, 2012 8:38 am

dan, they are not "tied together" so to speak where if one improves the other goes up or down. Generally speaking, a good window will have a better DP and a better AI as well, but there is not a set rule. For instance, there are DP50 windows that range from an AI of .20 to .02. You really have to look at both ratings individually.

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Windows on Washington
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Re: Help me understand these DP ratings, please

#7 Post by Windows on Washington » Sun May 27, 2012 1:50 pm

HomeSealed wrote:dan, they are not "tied together" so to speak where if one improves the other goes up or down. Generally speaking, a good window will have a better DP and a better AI as well, but there is not a set rule. For instance, there are DP50 windows that range from an AI of .20 to .02. You really have to look at both ratings individually.
+1

This is from my buddy a few posting up named Oberon....

The DP rating of a window or door is based on laboratory pressure testing in pounds per square foot or psf.

Air, water, structural is a three part test that determines much about a window's overall performance. Air infiltration is the first phase, water penetration is next, and structural is the third part of the test.

Windows are tested for air infiltration simulating a 25mph wind or a 1.56PSF pressure load - air infiltration is treated separately from both water infiltration and structural and it is independent of the design pressure of the unit. Said again - the air infiltration rate in a window is not based on the design pressure rating of the unit.

Both water penetration and structural testing, on the other hand, are based on the window DP rating. Water infiltration is tested at 15% of the design pressure and structural is tested at 150% of DP rating.

What this means is that a window with a DP30 is tested for water infiltration at 4.5psf (15% of 30psf) while a window with a DP40 is tested at 6psf (15% of 40).

A window with a DP30 rating should be able to keep out rain when its driven by 42mph winds and a window with a DP40 should be able to keep out rain when driven by 49mph winds...so while water infiltration is DP related - and air infiltration is not - the nature of air and water infiltration is different.

The structural rating of a window is as much about the glass as it is about the frame and sash system. In order to get a higher DP rating the window manufacturer has to consider the thickness and possible heat-strengthening (or tempering) of the glass as well as the use of higher-end hardware and good quality sealants in the frame and sash system. But, interestingly, there is nothing in the structural rating that specifically requires that the unit be air-tight.

A window can leak air like a sieve and still achieve an excellent DP rating. Likewise a window that is sealed tightly can have a lower DP rating but excellent air infiltration numbers. Obviously there are also many units that have both excellent air infiltration numbers and a satisfactory DP rating (relating to both structural strength and water infiltration).

Simply stated, the relationship between DP and windspeed is -- "the ratios of the design pressures in psf are the square of the ratios of the wind-speeds in mph".

A window with a DP30 is rated to a pressure level equivalent to a 110mph windspeed, but it is tested (for structural) at a pressure equivalent to 164mph.

A window with a DP40 is rated to a pressure level equivalent to a 127mph windspeed, but it is tested (for structural) at a pressure equivalent to 190mph.

If you are curious about calculating the numbers yourself, a while back (at the request of a specific window company as a matter of fact) I wrote a couple of simple formulas that will allow you to do so...

If wind-speed is known, then:
W/25 * 0.0624 * W = psf
Where W = wind-speed

Or, if Design Pressure is known, then:
SQRT(psf) * 20.01 = wind-speed


dandidit
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Re: Help me understand these DP ratings, please

#8 Post by dandidit » Tue May 29, 2012 10:31 am

Thanks for all of the information - it is much appreciated.

As of now, I'm comparing the following brands:

Okna (500 DX)
Soft-lite (Imperial)
Sunrise (Resorations)
Paradigm (8300 series)
Simonton (5500 reflections)

All are triples with a U value 0f .20, give or take +-.02

Air infiltration is important to us because we live in upstate NY on a hill (wind) and it often is in the teens/20s in the winter.

Paradigm has extremely competitive pricing (I was surprised), but I'm not sure how they stack up against the other windows - opinions on the above?

I'm working on a spreadsheet and will post to the group for review/insight.

Thanks

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Windows on Washington
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Re: Help me understand these DP ratings, please

#9 Post by Windows on Washington » Tue May 29, 2012 11:08 am

Those are some good brands there.

I prefer the Imperial LS as compared to the Imperial Pro but both are solid units.

The Okna and the Imperial LS will have the two lowest Air infiltration numbers of that group but once you get to 0.07 and below, the differences become less stark. The Simonton and Paradigm are probably the bottom two of that grouping but they are still decent windows.

The Simonton is probably not as air tight as you want and I don't know the Paradigm numbers off the top of my head but I would be willing to be they are not as good as the Okna, Soft-Lite (Imperial LS), or Sunrise.

If you are concerned about air leakage, take a look at the Okna EnviroStar and the Soft-Lite Elements. The are both 0.01 and very tight.

dandidit
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Re: Help me understand these DP ratings, please

#10 Post by dandidit » Tue May 29, 2012 12:09 pm

Thanks for the input - I am looking at the Imperial LS (as you mentioned).

I will have to see about the Okna EnviroStar (wasn't aware of it before).

Check out the Paradigm numbers: http://www.paradigmwindows.com/pdf/test ... ium_dh.pdf

They looked very impressive, to me.

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Windows on Washington
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Re: Help me understand these DP ratings, please

#11 Post by Windows on Washington » Tue May 29, 2012 1:10 pm

Pretty good.

I usually like to look at the test report and see how that window was prepped but the numbers look solid. The sample sizes on some of those other units is too big but the 100-110UI range is okay.

dandidit
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Re: Help me understand these DP ratings, please

#12 Post by dandidit » Tue May 29, 2012 1:13 pm

Where do you find the test report? or, is that something you have to request from the manufacturer?

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Windows on Washington
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Re: Help me understand these DP ratings, please

#13 Post by Windows on Washington » Tue May 29, 2012 1:25 pm

Normally you would have to request it.

Jakester
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Re: Help me understand these DP ratings, please

#14 Post by Jakester » Fri Oct 14, 2016 7:34 am

dandidit - so what windows did you go with then?

Ricknez
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Re: Help me understand these DP ratings, please

#15 Post by Ricknez » Fri Oct 14, 2016 8:17 am

Jakester wrote:dandidit - so what windows did you go with then?
Both soft lite and okna have very high dp ratings. Paradigm, not so much.
The Okna 600 series ( EcoPro) has a high DP rating and its a sharp looking window.
Last edited by Ricknez on Sat Apr 01, 2017 2:39 pm, edited 1 time in total.

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