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Master Window Cleaners of America

MWCoA Special Question and Answer Session

Today we are interviewing Cliff Monroe.

Mr. Monroe is employed with Arch aluminum & Glass Co. Inc. out of Tamarac, Florida.

He is their Senior Manufacturing Specialist. He has been in the glass business since 1970, initially working for Guardian Industries, then Milgard Mfg., Coolidge Glass Co. and Commercial Insulated Glass. He is a member of the Glass Association of North America of which he is on the Board, Chairman of the Tempering Division and Chairman of the Tempering Educational Seminar, on the Board as Treasurer for the Glazing Industry Code Committee, member of ANSI, ASTM, ASHRAE, IGCC and SGCC.

We are going to be talking about fabricating debris in connection with tempered & heat treated glass. As a window cleaner, I don't expect glass to be perfect, but I expect that each tempering plant will produce quality glass. But, as we know, all tempered and heat treated glass are not equal and some are much worse than others. As window cleaners we are looking for a standard.

This is a long and complex interview. I hope I did the best to keep everything in terms easy enough to understand. I don't believe we came to a conclusion, but we got the subject out into the open air. If you have any questions for Cliff Monroe from this, e-mail them to me and maybe we can get Cliff to answer them and add it to this- Director@mwcoa.com


1- Would you acknowledge that there are quality differences in glass tempered or heat treated at different plants? Could you explain why?

Cliff Monroe -

Tempered or heat strengthened glass have prescribed surface tension ranges under ASTM C- 1048 (MWCoA note- these links to these standards are vague and you often have to buy the standard. Why? I don't know. I guess it's just a money maker for them. They should give it to those who want to try to understand it. JMO-http://www.glasswebsite.com/techcenter/Information/index.asp ) that either product must be within to be considered suitable for their prescribed application. In addition tempered glass must meet impact testing criteria under CPSC CFR 1201

( Info on this- http://aec.ihs.com/document/abstract/RSUAJBAAAAAAAAAA )

and ANSI Z 97.

( Info on this- http://www.ansiz97.com )

Any superficial differences may be dependent upon the operations location, elevation, temperature, and humidity, general environment in addition to roller wave, bow/warp and edge condition which may influence the appearance of the product.

All heat treating oven operations are not built nor operated the same from company to company and sometimes even within a company. I would venture to say with all due respect, each window cleaning company may not clean glass the same as the other, dependent on some of these same influences.

Reputable fabricators, in my opinion, do their very best to supply a product to the customer that meets or exceeds the customers expectation. I would guess this applies to any type of business.


Agreed. Most fabricators do a very good job with fabricating heat-treated products BUT it seems some don’t even try and think it’s the responsibility of the window cleaning industry to adjust their cleaning procedures to conform to what we consider a “Defective” product. If I clean a window from let's say 15 years ago or longer, there are no defects; ie: Fabricating Debris, I use a razor blade free of debris and rust and there are no scratches from razoring the glass. If I use a razor, even used and abused with no debris or rust, I can not scratch the glass. Would you agree with this? I was once skeptical but I have tried it and it is true.

Cliff Monroe -

When using a blade on glass heat treated 15 years ago there is some level of probability that you may or may not have found fabrication debris. Glass washers, conveyors, ovens etc were not as refined regarding their maintenance as they are today.

Have you adjusted your life style or products used in window cleaning over the last 15 years ago.

I will revert back to my silk shirt story, if you do not comply to the manufacturers recommended cleaning instruction, you damaged or maligned the material thus you’re responsible.

I would disagree on the razor blade not scratching the glass, it will. Looking at in the right lighting conditions with or without magnification it’s there.


2- What should the glass surface quality be?

Cliff Monroe -

It is important to note that our charge as a fabricator is to provide our customer material that meets the optical quality of the standards out there. That includes the ASTM standards that have been used in the building industry for years, all over the world. Heat treated glass surface quality should at a minimum meet or exceed requirements of ASTM C-1048.( http://www.astm.org/Standards/C1048.htm if you want to learn a little about this standard.)

Someone asked me why do we not see the same problems with automotive glass as we do with residential or commercial architectural glass when it comes to “fabrication debris”? Over time the methods used to clean automotive glass have evolved. There was a time people used metal blades to remove ice and snow from automotive windows. I would guess today there aren’t many people (including professional window cleaners) that use a metal blade to remove ice, snow, or mud from the automobile glass. Doing so would identify some level of “fabrication debris”. With all due respect, would one consider the windshield or back lite glass fabricator at fault?


First of all, I doubt metal scrapers were ever used to remove snow from automotive glass, but that’s not the point. Scrapers that are sold to remove snow off automotive glass are manufactured from hard plastic and if there was EXCESS “Fabricating Debris” present, it would scratch the glass, just like a “Metal” scraper and that’s a fact. And, windshields are NOT heat-treated, so there is not an issue with the windshields.

Cliff Monroe -

“What should the glass surface quality be”: what is the level of glass surface quality for window cleaning heat treated glass you are looking for? What determines, in the window cleaning industry, a lite of glass is defective with regard to fabrication debris? How much fabricating debris is acceptable? How many microscopic surface particles are acceptable in a lite of heat treated glass?


I do believe that if the glass is properly taken care of, As Guardian Glass does ( I have seen there product many times, I am certain that Arch Glass is high quality also ) But there are companies putting out glass with Fabricating Debris on the glass. I also believe it is there because they are taking short cuts in the cleaning process. Am I wrong?

I believe the end customer would like to have a say on that issue, especially after they have experienced glass scratching and more importantly after they have read all the facts about EXCESS Fabricating Debris and how it can be easily avoided.

Cliff Monroe -

In the Midwest or in snow country in the 50-60’s, metal scrapers were used, I have two brass window scrapers if you would like to observe. You indicate that “scrapers that are sold to remove snow off automotive glass are manufactured from hard plastic and if there was EXCESS “Fabricating Debris” it would scratch the glass just like “Metal” scraper and that’s a fact. And, windshields are Not heat-treated, so there is not an issue with windshields” I did not say anything about windshields, I indicated automotive glass. The next time you look through a pair of polarized sunglasses and see iridescence markings on the window of a car or pick-up you will be looking at heat-treated glass.

I would agree with your first paragraph only to an extent. I would guess Guardian for the most part cleans their oven processes in a similar or like manner as we do (so you’re aware Guardian is not a big commercial window fabricator they supply glass to be fabricated). There very well maybe operations out there taking short cuts. I would guess the same applies in the window cleaning business.

I believe the customer would also like to be educated on the fact that there is a disclaimer for all flat glass heat-treated or otherwise relative to the use of metal scrapers and what the manufacturers recommended cleaning instructions are. Just like you car care, clothing, basically all products. Jack, it’s easy for some to point fingers and blame others, but what are you doing that is constructive to prevent the scratching from blades. Blaming others is not going help your fellow window cleaner.


3- I understand that when washing glass, usually the fabricator will need visually clean (standard) or critically clean (for laminated and coated glass). Is that correct?

Cliff Monroe -

To my knowledge there is not a written standard within the glass industry commercial or residential that determines what is quantified as “clean” or “critically” clean glass within a glass fabrication facility. Individual companies develop their own internal standards based on the expectation of the type of finished product quality they desire. A company that applies vacuum deposition material to a glass substrate may wish to insure the glass is free of any and all possible contaminates that may prevent adhesion of base metals to the substrate and have the highest levels of surface purity to prevent any discoloration or staining in the future or through a respective warranty period. The fresher the glass is from a float line the less chance of various types of surface contaminates may come in contact with the glass surface to be coated. Even with fresh substrate, these companies have extensive scrubbing and oscillating brush glass washers, some may use a level of surface striping to gain maximum cleanliness.

Typical commercial or residential laminated glass does not require the same intensity of cleanliness as glass to be coated in a vacuum deposition process. Adhesion between the glass surface and the interlayer are critical. Could there be “fabrication debris” on or between the glass surfaces laminated? Yes.

Glass fabricators, insulators, and window manufacturers have developed cleanliness criteria for their product based on compatibility of materials used with their product, component material long term performance, and customer’s expectations.


It sounds like you are confirming there is an ability to get the glass much cleaner if fabricators “wish to insure the glass is free of any and all possible contaminates.”

So if a client has been experiencing “EXCESS” Fabricating Debris (resulting in excess scratched glass) on their heat-treated glass, it could be improved with the desire for proper facility maintenance?

Cliff Monroe -

I am referencing surface contaminates that may affect product color, staining, lack of adhesion typical in coating, silk-screening, insulating glass products etc.

Again you use “Excess” without any quantification as to what it represents. You mention Excess scratched glass, are you saying that some level of scratching is acceptable with a scraper? If so how do you quantify “excessive”?


4-Should there be some kind of standard for surface quality?

Cliff Monroe -

There are standards for each type of flat glass product manufactured or fabricated currently available through ASTM; C 1036 for Float Glass, C 1048 for Tempered & Heat Strengthened Glass, C 1072 for Laminated Glass, C 1376 for Coated Glass, C 1503 for Silver Glass etc.

Specific to cleanliness of glass surfaces within a float glass or fabrication facility, there are many standards or requirements dependent upon the applications involved with contact to the glass surface. Some are proprietary and some are not.


Are you confirming the ability of fabricators to get glass “Cleaner’ if they desire?

Cliff Monroe -

Should there be a “standard” such as an ASTM standard? I would say that’s up to the industry.

I see no advantage for the glass industry to require fabricators to upgrade their operations when they can heat-treat glass now without ANY standard, as long as it passed the visual ASTM Standard.

If window cleaners believe there is a need for such a standard then one should pursue it through ASTM.


I think window cleaners would be outnumbered, but if we could get enough builders who understand the importance of facility maintenance, then we might seriously consider joining.

Cliff Monroe -

Cleaning is needed respective of the product assembly and application. How does the window industry judge their product cleanliness, is there a standard or format I can use when my residential windows are professionally cleaned to judge whether or not they are truly clean? According to your industry websites and forums there are plenty of window cleaners who do not clean glass the best they can unless the customer requires it. How does that apply to your question?

ASTM is made up of all professions not limited to glass. Go to www.ASTM.org and view the multitude of standards for every item imaginable.


5- Are there standards for facility cleanliness, standards that each plant is held to?

Cliff Monroe -

To my knowledge there is no specific GANA directive on cleaning glass in a float glass or glass fabrication facility. There may be some specific to hospital applications or highly critical environments that I am not aware of.

Our goal as a glass fabricator is to obtain optical perfection within the ASTM specs. If one were required to use a microscope to find a particle of any type on a glass surface it would be virtually impossible 80,000+ sq ft plant that is producing hundreds of thousands of sq ft of glass per week.

With all due respect, are there standards of cleanliness within the window cleaning industry? How does your customer determine if the cleanliness meets his expectations?


In our industry, it “IS” all visual, but they sure don’t expect their glass to be scratched when we’re done. It is both fortunate and unfortunate that our industry with few exceptions is unregulated

Cliff Monroe -

Jack, in our industry from an optical perspective the glass business is judged the same way; glass to be scratched “visual”. Additionally, your customer should not expect the glass to be scratched. Why then are some window cleaners asking to have waivers signed that imply they are not responsible for scratched glass? Is that not an omission of guilt knowing that if they apply certain methods in cleaning there is a potential scratching? I would think there needs to be regulation in the window cleaning business that will insure prior to signing any waiver that the customer is fully informed as to what the manufacturers’ product warranties and cleaning instructions may be. Maybe the “manufacturers cleaning instructions” should accompany your industries scratch wavier.


6-Shouldn't there be a maintenance Standard for the equipment in every fabricating facility so accountability could be attached?

Cliff Monroe -

Many companies are using preventative maintenance systems to insure product quality consistency and equipment longevity.

When talking about heat treated window cleanliness the issue is only relevant when a problem arises with a technique used to clean a glass surface creates scratched glass.


Or, when a coating or laminate doesn’t pass the customers expectations, correct?

Cliff Monroe -

Passing a customer’s expectation may not be an accurate way of stating such. Customer expectations may be greater than the standard quality provided. If the customer had greater expectations than what are consider as “standard” he may be disappointed if he did not express those expectations prior to the purchase and may feel short changed. Every industry has minimum standards. Correct me if I’m wrong but I would think this is applicable in your business also


7- Is there a standard for washing glass before it's tempered or heat treated? My understanding of the tempering or heat treated process is that the glass is sized, during this time glass fines ( or shreds of glass ) fly around and some remains in the glass too be tempered or heat treated. Some plants clean the glass, with water, others with air of a brush. Is there a standard from GANA? Should there be?

Cliff Monroe -

To my knowledge there is no such standard.


This could make the difference in the end product, don't you think?

Cliff Monroe -

When flat glass is scored surface fractured with a diamond surface cutting tool, there are small microscopic glass chips that arise from the score and lay on the glass surface. The flatter the surface the glass is resting upon when scored (the less compression or tension the glass substrate surface is placed in) the less fragmentation. The use of the correct cutting wheel, cutting wheel pressures and cutting wheel speeds are all contributors to glass surface scoring and score running/breakout. Glass chips on the surface of the glass in correctly managed glass washing process should not get beyond the wash and rinse sections of the glass washer.

Conscientious glass fabricators take precautions not to use an air lance or air brush (compressed air is very expensive) to blow off or remove glass chips as a manner of good housekeeping.

In today’s information world of glass fabrication, those who do not wash their glass prior to heat processing deserve what they may receive.


Agreed, but does the builder deserve scratched glass as a result of “EXCESS” Fabricating Debris from a poor quality fabricator? And, does the builder deserve to be subjected to GANA’s bulletins, which defends the incompetent fabricators? Do you believe that G.A.N.A. should make an effort to weed out or push for a better quality product from fabricators who send out inferior products?

Cliff Monroe -

GANA does not have a standard for glass cleaning that I am aware of.


I find it strange that GANA has suggestions for our industry, but chooses to side step their own industry on this point. Nothing in writing, so no accountability?

Cliff Monroe -

GANA does provide fabrication training seminars for glass fabricators. This is done in conjunction with equipment manufacturers and membership’s participation to help educate new members and first line operators and supervisors on how to cut, clean, and heat treat flat glass.

You ask if there should be a “Standard” there are standards and procedures used by those of us that place a concerted effort in providing a product to the market that meets or exceeds the customer’s expectations. Once again I will say that if there are people out there that feel there is a need for this type of standard, there is no one stopping them from being a member of ASTM and developing it.


So noted.

Cliff Monroe -

One standard would not cover every aspect of glass fabrication. I think you need to tour an all encompassing glass fabrication facility to best understand what you’re asking. All due respect, shouldn’t there be a standard for professional window washing?

In re: the builder normally does not receive scratched glass; I would guess he’s generally content with the product upon receipt. When a blade is used by a window cleaner the potential for scratched glass dramatically increases. Does a builder or home owner deserve to have his investment scratched by a window cleaner?

As a member of GANA I do not believe GANA defends any fabricators in any way shape or form. Do window cleaning organizations (IWCA) weed out or recognize incompetent window cleaners? How about those window cleaners that have scratched glass on an entire home or business and never mentions it to the customer until they are confronted? Was the glass scratched before they started?

This statement is ridiculous, how do you stand in judgment of the GANA organization in this regard when your own organization has nothing in writing or a standard to be judge upon? There are those in your industry that profit from fabrication debris as a forefront to making money and pretending there is no other way to clean the glass. Getting someone to sign a document that implies the window cleaner is not responsible for his lack of knowledge, education or common sense. That is not accountability.


8- I've heard stories about brushes in the glass washer not even touching the glass and washers that didn't have any water in them. Should the window cleaners be liable for this kind of negligence if while cleaning the glass a scratch happens, after all that glass might pass some ASTM standard?

Cliff Monroe -

With some of the soft-coat (vacuum deposition) products available today some fabricators may very well not use top brush contact onto the coated surface of the glass within their glass washers. Normally when not using top brushes, this method requires flat glass washers to have the glass surface exposure to high pressure pre-rinse and wash/rinse water sections that remove any surface contaminates. Keep in mind that these same washers most likely are fully utilizing their bottom brush sections to prevent any transfer of surface dirt etc from exiting the washer.

The majority of commercial glass and a high percentage of residential glass is vacuum deposition/soft coat product. Fabricators that are processing soft coat product will clearly know if he is not using water in his washer. Typically the same glass washers used for soft coat washing are also used for non-soft coated product.

If you are implying that “fabrication debris” is a negligent act on behalf of the fabricator, I would challenge that statement.


I believe we need to state once and for all; it’s the “EXCESS” Fabricating Debris that we believe is “Negligent” and separates the irresponsible fabricators from the reputable fabricators. Do you agree?

Cliff Monroe -

The industry and manufacturers give notification of handling and cleaning instruction regarding finished product to those who handle, process, glaze, and clean glass. When these instructions are not followed, who is responsible? Can you give me another example of where a manufacturer supplied instructions are ignored and the manufacturer is held responsible when the user failed to follow the manufacturer instructions? Try it with your automobile windshield, use a metal blade on it and see if the manufacture replaces it at no charge to you.


I agree, but when a fabricator does not follow the “suggest” maintenance schedules offered by the manufacturers of their equipment, they will be held liable.

Cliff Monroe -

What is “Excess”. Quantify it for me, what is acceptable level of fabrication debris, quantify it.

If a window cleaner does not follow the manufacturer’s recommended cleaning instructs who should be held liable? Again, think of the silk-shirt cleaning instructions


You seem to like to fall back on this line.....I don't think you find a lot of Fabricating Debris on a silk shirt.


9- How much more difficult would it be to make this the standard for tempered glass?

Cliff Monroe -

If you’re referring to in-house standards for laminated glass to be applied to heat treated glass, there is little to no difference if you process soft coat product in both operations. Some heat-treating oven glass washers are far more high tech than those that laminate. Processing soft coat product through a glass washer is more demanding and requires more water control and measuring devices than processing standard laminated glass products.


10- How bad does the heat treated glass surface have to be before it considered a defective surface?

Cliff Monroe -

I am not clear on this question. If you will permit me one last comment, when you purchase a silk shirt and the instructions on the label include recommendations for cleaning, do you follow them or do you just put it in the wash with your Levis & cotton shirts? If you’re answer is no, why not? The use of tempered and heat strengthened glass has exploded in the last 10 years thanks to the new energy & decorative technology of glass out there. Our industry has had to change our processes inside our plants dramatically. Different equipment, different cutting oils, different handling, different cutting, edge deletions, washing adjustments (like the brush issue) heat treating oven modifications and redesign just to process these products. This glass is NOT your father’s glass. So in turn while the glass industry has had made significant sophisticated changes, the window cleaner industry sticks (with regard to blades) stubbornly to its ways.

There’s tremendously more heat treated material being produced now compared to 10 years ago, meaning there'll be more heat treated surface issues available. GANA has attempted to explain the difference in order to avoid the difficulties. Instead of trying to work with the new generation (like the glass people have had to) a segment of the window cleaning industry has chosen to fight it by resisting change, sticking with old methods (some are profiteering) instead of working to develop a change for a better way. And while there are situations that have been happening even before the advent of new glass and increases of heat treatment, the bottom line is still that the glass industry has offered insight on the surfaces and it really should be up to the window cleaners to develop ways to clean the product without damaging it. Like was noted with the shirt argument, if you knew that your way of processing a product would have a probability of damaging it, why do it? Wouldn’t you look for different and better ways? There are few businesses in the world that have not had to endure these types of change to survive. All that being said, our two industries are at an impasse. Collectively we cannot afford to be at odds with one another, right or wrong, change is required to survive. There are several governmental and environmental organizations out there that would love to see less glass used in buildings. If successful there will be a negative effect on both of our industries. How much more could we do together?


I believe both industries need to consider their “Client” before taking a position. The facts still remain they are our client. We all have a responsibility to consider our clients interest.

Some builders neglect to protect their glass, some fabricators neglect to fabricate the highest quality heat-treated glass of their ability and some window cleaners scratch glass without knowing how it occurred, but as all the facts on “Fabricating Debris” becomes easily obtainable, there will be choices to be made and then the builder will be making all the decisions.

As a side note and maybe another question, you seem to be saying that a razor blade would scratch the glass alone. Would you say that is true?

If you say a razor will scratch the glass, have you ever tested that?

I, as many other window cleaners have tested razors on glass. If a razor will not scratch glass, when glass is scratched, what causes the scratches?

Cliff, I know this was a lot of work, but I do believe when it is done, both industries will learn from it. I can not thank you enough for going through this. If there is anything you'd like to ask me, please feel free.

I do believe that things can improve between the two industries. I also think that it is going to take some work on both sides to come together. I believe there can be common ground in the middle. We both want the same thing. If we can get the quality guys to push the people who are producing less than quality glass to improve their product, it is better for all of us.

Cliff Monroe -

I would disagree with your comment on consideration of the client. The glass industry does take into consideration its clients because without them we do not exist.

Razor blades will scratch a lite of glass, the blade disturbs the surface. Or is the blade a perfectly flat edge are there peaks and valleys? A glass surface has countless peaks and valleys on its surface.

In summation;

The glass industry acknowledges and recognizes that there are glass fines at times on the glass; it is stated within ASTM C 1048-04 at line 7.6 Surface Particles. And the window cleaning industry is fully aware of this fact.

   The industry supplies its customers with manufacturer’s warranties which clearly state metal blades are not to come in contact with the glass surface. And the window cleaning industry is fully aware of this fact.

   People from many levels and segments of the glass industry have attempted through the Glass Association of America; acknowledged and have created papers and bulletins on glass fines. Once again the window industry is fully aware but ignores the facts.

It will soon be 2009 and some in the glass cleaning industry (fewer everyday) insistent on doing thinks today as were date 50-60 years ago, still blaming others for their short comings and lack of innovativeness to discover new or different methods of changing with the product requirements. If we worked together I would guess we could resolve this issue and concentrate on making money.


Cliff Monroe

Fabrication Debris Does Not Scratch Glass-Metal Scrapers DO


We disagree completely on your signature.

Jack Nelson - Director MWCoA

Cumberland, Md.




Cliff, Please tell me how you would clean this glass without a metal razor. This is very typical of what we run into with post construction clean-up.

Post Construction Cleanup Window

Compliments of Dan Fields

Here is an actual window that I had, before and after-

Before Construction Cleanup

After Construction Cleanup

As a window cleaner, what would YOU do to get this window clean?

Cliff Monroe -

Thx for sharing, I wouldn't have the faintest idea of how to clean the window. I would like to help resolve the best method and procedure. It's a shame that windows are treated this way. I wonder what would happen if the siding or brick or painted surfaces were treated in this manner. I would bet builders would prevent that from happening asap.