Replacement Windows

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Author Message Deborah Corr, CSI, CCCA (Unregistered Guest) Unregistered guest Posted on Wednesday, June 13, 2018 - 10:15 am:    I have an oversight role in several multi-family rehab projects. The Developer is planning to replace existing aluminum-clad wood windows installed in the 1980’s with new vinyl windows. The original specification was for Anderson Perma-Shield Narroline, double-hung, insulating glass, low-e glazing, air infiltration rate of .20 or better. Equals had to bear a NWMA Class A Label and were named as Pella or Weather Shield. Based on published expected useful life tables the original windows should have 20 years of life left in them. Two questions: 1. Is it reasonable to expect these windows to last another 20 years (assuming they are not currently damaged or in disrepair)? 2. If they are replaced, what current product is an in-kind replacement? Or what minimums should be specified to get an equivalent product (either wood or vinyl). John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1744 Registered: 03-2002 Posted on Saturday, June 23, 2018 - 12:51 pm:    Maybe they have twenty years left, but only an onsite assessment of their condition could tell that. Fifty years is a long time for a window to last, and one might get that if they, and the building they are in, were carefully maintained. I recommend that you start by analyzing the performance needed - resistance to air and water infiltration, thermal resistance, solar gain, possibly hurricane impact, and wind design pressure. You will need to use the North American Fenestration Standard, published by AAMA, and input from the architect and structural engineer for loads that they will experience. Building codes require meeting these standards, too. If you are not familiar with NAFS, it is quite a bit to digest, but its use will assure that you get the performance needed. As to construction quality and lifespan, it's my belief that once you have a product capable of meeting all that nature throws at it, you've gone much of the way to getting a long-lasting window. I also think that all of the major window manufacturers make very good, competitive products. Deborah Corr New member Username: drcorr Post Number: 1 Registered: 06-2018 Posted on Tuesday, July 03, 2018 - 01:05 pm:    Thank you John! I did find AAMA and the NAFS. As usual my search for information ends at a pay wall. I understand that is how standard setting organizations are able to exist and provide their important function, but purchasing standards is not feasible for me or my organization. Past experience tells me that the Developer will use the most inexpensive product available at the local home improvement store. I researched what products are available at these outlets and find some with no AAMA/WDMA/CSA101/I.S.2/A440 certification. Others are certified, with PG R-20 seeming to be the ‘floor’ for windows of the size and operation needed. I contacted Andersen to ask what would be a modern day replacement for the original window. They sent me information on their 100, 200, 400 and A Series. The ‘floor’ for these windows also seems to be at PG R-20. The AAMA website says the Entry-level Performance Grade is R-15. I would like to ask for AAMA/WDMA/CSA101/I.S.2/A440 certified windows with a PG equivalent to the original windows, but what is equivalent? That has been a difficult question to answer. It seems PG R-20 is a reasonable ask. Is that too low? This is for Multi-Family housing, wood-framed, single-story, four-plex designs, located in the middle of the country (not coastal). Yes there is a Project Architect involved. There are no local AHJs or codes. I can almost guarantee the Architect has no plans to go through a NAFS exercise. Dewayne Dean Senior Member Username: ddean Post Number: 159 Registered: 02-2016 Posted on Tuesday, July 03, 2018 - 01:15 pm:    Double Hung window mechanisms can be a maintenance nightmare. I wonder if they still open after 30 years. J. Peter Jordan Senior Member Username: jpjordan Post Number: 1047 Registered: 05-2004 Posted on Tuesday, July 03, 2018 - 03:30 pm:    The number in the rating indicates the pressure to which the unit is tested and 20 osf seems a little low. The R will govern the "gateway" or minimum size tested. The R designation will also indicate deflection and air and water infiltration permitted. I have put together a table that summarizes the AAMA ratings at http://www.jordanconsultants.com/a440-chart.pdf. You should get some input on the positive and negative wind pressures for the project. These will vary depending on the height of the building and how close to the edge (pressures are higher at the edges than they are in the field). If your building is more than a couple of stories. A great way to start on the wind pressures is to find out the local windspeed (see https://hazards.atcouncil.org/). My hunch is that you should be looking at a LC-30 unit but this really depends on project location and building height. J. Peter Jordan, FCSI, AIA, CCS, LEED AP, SCIP Greta Eckhardt Senior Member Username: gretaeckhardt Post Number: 77 Registered: 08-2013 Posted on Tuesday, July 03, 2018 - 03:35 pm:    Very nice chart, Peter! Thank you.