Anodized coating and PVDF Coating

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Author Message David J. Wyatt, CDT Senior Member Username: david_j_wyatt_cdt Post Number: 70 Registered: 03-2011 Posted on Thursday, March 20, 2014 - 09:45 am:    I am specifying aluminum entrance doors and frames for an elementary school. I have always understood (perhaps incorrectly) that anodized coatings, though limited in colors, are more durable than PVDF coatings where a lot of people are coming and going. Any comment or correction on this notion will be appreciated. The owner is biased in favor of PVDF coating, which can attain a 20-year (sometimes 30) warranty whereas the anodized standard warranty is only for 5. From what I gather from reading several PVDF warranties, the 20-year warranty coverage is limited to fading and chalking, whereas the typical anodized warranty covers fading, chalking, peeling, and cracking. Any comment or correction on this point will also be welcomed. In this particular instance, the color is not an issue, because the owner wants an aluminum appearance. What do the 4Specs experts think about this? Dave Metzger Senior Member Username: davemetzger Post Number: 504 Registered: 07-2001 Posted on Thursday, March 20, 2014 - 09:56 am:    There was a 4specs thread on this about 10 years ago--see: http://discus.4specs.com/discus/messages/3077/1041.html?1136828238 Dave Metzger Senior Member Username: davemetzger Post Number: 505 Registered: 07-2001 Posted on Thursday, March 20, 2014 - 10:00 am:    There was a 4specs thread on this topic about 10 years ago: http://discus.4specs.com/discus/messages/3077/1041.html?1136828238 David J. Wyatt, CDT Senior Member Username: david_j_wyatt_cdt Post Number: 71 Registered: 03-2011 Posted on Thursday, March 20, 2014 - 10:19 am:    Thank you, Dave Metzger! The link provided a very thorough and thoughtful discussion on this. ken hercenberg Senior Member Username: khercenberg Post Number: 736 Registered: 12-2006 Posted on Thursday, March 20, 2014 - 11:05 am:    David, that was indeed a great thread. Something that William touched on and that you may want to consider is that you do not want to use PVDF on your hardware. It is too soft and prone to damage from the oils in hands and rings on fingers. Stainless steel, nylon coatings on aluminum (HEWI is now part of Hafele), and other options may provide a better long term option if longevity is your goal. The other concern is whether people will use the hardware provided or simply push against the door itself. J. Peter Jordan Senior Member Username: jpjordan Post Number: 709 Registered: 05-2004 Posted on Thursday, March 20, 2014 - 11:43 am:    An update to the thread is that PVDF resins are now available in powder-coated coatings. It is my understanding that where new factory-coating facilities are being installed, the lines will use the powder coated process rather than a backed on liquid film as was typical 10 years ago. That is the reason that current standards do not really refer to film thickness, but simply to the AAMA standard. We do a LOT of clear anodizing in this area, and I will typically specify a Class 1 coating. You can get a 5-year warranty from a manufacturer, but in my experience, it lasts much, much longer. The clear anodizing is difficult to damage noticeably (as opposed to the color anodizing, expecially the dark bronze). We did some of the champagne anodic coating in the early '00s. There is a copper anodizing that is avaialable, but I have not had someone require is on a project. The resins make a big difference in appearance and longevity. Epoxy would seem to be desirable, but it "turns" with exposure to UV (especially the lighter colors) while PVDF is much more stable. The polyesters (the most common type of powdercoated resis) has a good range of colors with high gloss (as opposed to the low gloss of PVDF), but does not have the long term color stability. I would give serious consideration to a clear anodized, heavy wall door for a school. Damage from use (especially keys) is not readily apparent, and these doors are very rugged (especially with the continuous geared hinges). There was another thread in which one or more participants advocated mill-finish aluminum for marine environments. Having lived most of my life within 60 or 70 miles of salt water, I have to say that this is something I would never advocate. Although the mill-finish aluminum might develop an acceptable patina, most would see the patina as surface damage. Clear anodizing would provide some protection; PVDF would provide the most protection from the environment (not necessarily use). spiper (Unregistered Guest) Unregistered guest Posted on Thursday, March 20, 2014 - 11:36 am:    Our office has always favored anodized finishes in our work. Ken makes a good point about the hardware. In our practice the real key to entrance doors on schools is durability of function rather than finish. A good looking door that makes the owner happy at install will sour in a hurry if the hardware is not adequate. Full length gear hinges in heavy duty framing with heavy duty closers and panic devices are what we believe helps to keep our clients happy and our repeat business steady. ken hercenberg Senior Member Username: khercenberg Post Number: 737 Registered: 12-2006 Posted on Thursday, March 20, 2014 - 01:23 pm:    Continuous geared hinges are important. We worked on a college dormitory where our best and brightest youth were sticking broom handles between the door and frame, breaking the doors off the hinges, and using the doors to go hill surfing. Probably not going to happen at the elementary school level, but continuous hinges solves a multitude of issues. Still, that's not what you were asking about. G. Wade Bevier, FCSI, CCS, LEED-AP BD+C, SCIPa, USGBC Senior Member Username: wbevier Post Number: 51 Registered: 07-2004 Posted on Thursday, March 20, 2014 - 01:39 pm:    I concur regarding the continuous hinge option from a durability point of view. The Class 1 anodized is a good choice as well. It is not an apparent issue in this instance (due to using the clear aluminum finish) but the only caveat I have is when using a dark colored anodized finish and any repair has to be performed a few years down the road, that the designer may have to match a lighter shade to more closely match a existing frame that may have faded over time. Edward J Dueppen, RA, CSI, CCS, LEED AP Senior Member Username: edueppen Post Number: 6 Registered: 08-2013 Posted on Thursday, March 20, 2014 - 02:01 pm:    I have been enjoying this thread, but I think I'm missing something. For those who are proponents of using Clear Anodized Entrances, what is the recommended finish on the entrance framing, especially when it is part of a large storefront or glazed curtainwall? Do you propose a PVDF color similar to clear anodized such as Duranar Silversmith? I would appreciate any suggestions! George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 728 Registered: 11-2004 Posted on Thursday, March 20, 2014 - 04:33 pm:    Door hardware observations: Continuous geared hinges on aluminum doors are the preferred choice for hanging devices. Once in a while I see pivots still preferred by an owner, but most architects and institutional owners I work with want continuous geared hinges. Keep in mind that the door hardware you touch is most often not clear anodized aluminum. Pulls tend to be 630 (brushed stainless steel) and levers tend to be 626 (brushed chrome). Exit devices can be similar, or powder coat. Anodized parts sometimes occur on exit devices, but not in an area that would have the most wear. For an illustration, see: http://us.allegion.com/IRSTDocs/DataSheet/105229.pdf (pardon the product placement, and feel free to see similar from our competitors - I'll let you look up their documents on your own). Powder coat finishes hold up pretty well - and you can get them on locksets and pulls, but usually as a special order, or from Hewi/Haefele type manufacturers. Final personal observation - have your hardware specification consultant do the hardware for aluminum doors, NOT the door manufacturer. We tend toward the more robust products - they tend to want to use off the shelf products from their warehouse, that may be serviceable, but not necessariy as tough as you might want. This is especially important for high use or abuse environments. George A. Everding AIA CSI CCS CCCA Allegion PLC (formerly Ingersoll Rand) St. Louis, MO Sheldon Wolfe Senior Member Username: sheldon_wolfe Post Number: 746 Registered: 01-2003 Posted on Thursday, March 20, 2014 - 05:11 pm:    Avoid chrome-plated finish for levers, knobs, and other contact parts. Use stainless steel, unless you like the look of mixed brass and chrome. spiper (Unregistered Guest) Unregistered guest Posted on Thursday, March 20, 2014 - 05:55 pm:    To address Edward's question. The entry to a school (assuming it is the main entrance area) has become a focal point of building security in our practice so the inclusion of large storefronts or curtain walls is typically avoided. Our typical approach breaks the entry area down into smaller openings so safety glazing or even bullet resistant glass can be utilized without blowing the budget. We still may have multiple doors as well as sidelights and maybe transoms but not large window walls. This allows us to treat the entry as an individual element that may or may not match the larger framing finish. Not that I review my response I realize that I haven't actually answered your question at all, sorry about that. Of course fortifying the entry creates a somewhat false sense of security because you can typically walk 30' in either direction of the entry area and find typical 1" insulated glass in the classroom windows, but that is another discussion altogether. James Sandoz, AIA, CSI Senior Member Username: jsandoz Post Number: 147 Registered: 06-2005 Posted on Friday, March 21, 2014 - 10:04 am:    George, your comment about door hardware on aluminum doors is one of the reasons I go to 4specs discussion forum every day. I was already aware that there is a difference in what a good hardware consultant specifies and what the manufacturer will supply as a default but it was good to be reminded. I have to believe (or at least hope) there are young design professionals out there who will see this and be made aware also. I will add that almost all the Class 1 anodized finishes I have seen over the past 20 years look pretty good regardless of their age and where they are located.