Reflections

Glass Selection and Specification

J. Peter Jordan, FCSI, AIA, CCS, LEED™ APJordan Consultants, LLCHouston, Texas

Houston Area Glass AssociationJuly 12, 2012

Jordan Consultants, LLC• Jordan Consultants, LLC, seeks to add value to its

clients’ design and construction through building product research, evaluation, and selection, production of construction specifications, and advising on sustainability, project procurement, and building envelope performance. Since its formation in 2006, the firm has provided specifications for more than 350 projects in Texas, Florida, New York, and Connecticut.

• Mr. Jordan has practiced in Georgia, Hawaii, and Texas, and has worked on projects in Texas, Florida, California, New Mexico, New Jersey, Hawaii, and throughout the Pacific Rim. He is a member of AIA and CSI, a Certified Construction Specifier, and a LEED Accredited Professional.

Introduction

• When I first started working in architectural practice in the mid-1960s, glass options for glazing were limited to 1/4-inch glass in a few tints.

• Architects must now select from a variety of glazing materials and assemblies of those materials, each of which offers a slightly different advantage in performance or appearance.

Introduction

• They generally don’t do it very well.

Introduction

• Have you seen specifications for:• 1/4-inch polished plate?• “No tong marks” on annealed

glass?• LOF as a specified

manufacturer?• Low-e glass; just “low-e glass”?

• Have you been scratching your head, asking “What th’ heck?”

Introdction

• This presentation is a quick overview of:• What architects should be considering in

selecting and specifying glazing.• Constraints in specifying glass.• How to respond to an ambiguous or

defective specification.

I can see clearly now…

Glass (as you know)

• Glass is a clear, rigid, supercooled liquid, that is manufactured primarily from silica (sand) soda ash, and limestone with traces of other materials.

• Glass may be annealed, tempered, bent, formed, coated, or laminated to provide complex assemblies for functional and decorative purposes.

Glass and glazing

• Generally, glazing preserves visual contact between two spaces, usually between inside and outside while providing a weather barrier.

Glass and glazing

• Glazing may also serve as a barrier for • Thermal energy transmission.• Sound transmission.• Security.• Ballistic and blast protection.

Glass and glazing

• Glazing may be simply glass, but glazing may also be:• Plastic (acrylic or polycarbonate).• Clear ceramic (fire-rated glazing).• Assembly of one or more of any products

listed above.

Glass

• The standard for commercial glass is ASTM C 1036 “Standard Specification for Flat Glass.” This specification covers:• Clear and tinted flat glass (annealed or float

glass)• Wired flat glass• Patterned flat glass

Glass Selection

Glass Selection

• Ten years ago, PPG Industries ran a marketing campaign to Architects:

“Looks are everything!”

Glass Selection

• It wasn’t really true then, and it is even more complex today:• New energy codes.• New windstorm codes.• New security concerns.

Design Intent

• The Architect will have an idea about what the building looks like…• Is the surface smooth or

textured?• Is the surface shiny or

matte?• What color (or colors) is it?• Is the building structure

concealed or expressed?• These concerns affect the “Visual

Quality” of the building design.

Design Intent

• The “Visual Quality” then needs to be balanced against concerns for:• Thermal comfort• Structural performance• Cost

COST

Glass Selection

• Glass selection should be made in response to:

Visual QualityThermal Performance

Structural Performance

Glass Selection

• Questions:• Clear?• Tinted? What color?• Reflective? What color?• Screened? Pattern or image? What color?

Visual Quality

Glass Selection

• Questions:• Wind pressure?• Burglar resistance (smash-n-grab)• Debris impact resistance?• Bullet resistance?• Blast resistance?

Structural Performance

Glass Selection

• Questions:• Solar heat gain coefficient?• U-value?

Thermal Performance

Glass Selection

Visual QualityThermal Performance

Structural Performance

COST

Glass Selection

• At the end of the day, glass selection will be made in response to:

Glass Performance - Cost

• Cost of the glazing unit is determined by:• Base cost of glass as manufactured• Cost of fabrication processes such as

• Application of reflective coating• Application of low-e coating• Application of fritted coating• Lamination process (two plies or three or

more)• Insulted glazing fabrication (two lites or

three)

Glass Performance - Cost

• So…• Cost of glass + application of low-e coating

+ insulated glazing construction (with two pieces of glass) will probably cost less than

• Cost of glass + application of low-e coating + application of reflective coating + insulated glazing construction (with two pieces of glass) will probably cost less than …

What Does the Architect Want?

What Does the Architect Want?

• Choose one…• The best looking stuff• The good stuff• The most expensive stuff• The cheapest stuff• The right stuff

What Does the Architect Want?

The real answer is

The most economical product that meets the critical design criteria,

including

Visual qualityThermal performance

Structural Performance

What Does the Architect Want?

How does he go about it?

Drawings and Specifications

Drawings and Specifications should communicate the Architect’s “design intent” to Bidders for pricing and Contractors for construction.

Drawings and Specifications

• What if critical decisions have not been made?

• What if the Architect’s “design intent” is not clear?

Drawings and Specifications

• Ambiguity should have a price…• The price should not undermine the

critical design criteria.

What to do?

What to do?

• If you are bidding,• Get a copy of the Drawings and

Specifications, and get them early enough for a thorough review.

• If there are discrepancies, conflicts, or omissions, ask questions.

• Don’t make an assumption which may lead to submitting a bid for the wrong stuff.

• Submit an RFI on a timely basis.

What to do?

• If the Architect says “Bid it the way I drew it,”• Consider walking away from the job; it

could be a gigantic headache and you may be expected to provide stuff you didn’t include in your price. You may or may not get paid for this.

• Consider carefully whether you should submit a bid for what you think the Architect wants or submit a “lowball” bid and request a change order later.

What to do?

• If you have a contract in place,• Confirm product selections through

submittals before ordering products.• Allow plenty of time for multiple submittals.• Don’t hesitate to inform everyone if the

direction that the selection process is going will mean a change order.

What to do?

• If the project is seeking LEED certification,• Thermal performance will be important if

not critical.• If there is a significant amount of glass on

the project, location of manufacturer and fabricator may be critical.

Conclusion

Conclusion

• The glass industry has evolved over the last 50 years, becoming more complex in the types of products offered.

• At the same time, glass performance and aesthetics have become more sophisticated and, in some ways more critical.

• Architects can choose from a variety of products and assemblies to meet specific requirements.

Conclusion

• However…

Conclusion

• Effective product selection and specification requires more attention and knowledge than ever before.

• Product representatives and Installers provide helpful information helpful, but to be effective, they must be given design criteria that are meaningful.

Conclusion

• Architects must become more informed so that they can make good use of the expertise that is available.

Conclusion

• If this process comes together so that intelligent decisions are made,

• Then…• Meaningful specifications that really do

communicate design intent can be developed, and

• Glazing product manufacturers and installers will better understand the requirements for the project.

END OF SECTION

Houston Area Glass AssociationHouston, Texas

Houston Area Glass AssociationHouston, Texas

J. Peter Jordan, FCSI, AIA CCS, LEED™

AP

Jordan Consultants, LLC

50 Briar Hollow Lane • Suite 235WHouston, Texas 77027

Tel: (713) 366-0320 • Fax: (713) 589-5493jpjordan@jordanconsultants.com