LGMI R

  

23 Jan 2013--Fabric Roofs 
As we have stated previously, we are going to be taking the ideas developed in this column over the last couple of years and developing them into design practices.  This is how it works.  We will provide the basic narrative here for one design practice each week.  We will keep it open for comments for one month.  After that, we will finish it in formal form and offer it for sale at a modest price.  Here is where you come in.  If you make a substantive contribution to a standard, the organization for which you work will be granted a pro bono license to use that standard with its current issue number for as long as you like.  We have had good response so far!  Contribute, please.

This week's:  Fabric Roofs  (LGM 2013.012.01 when issued)

Reference:

 

The biggest performance advantage of tensile fabric structures is its strength to weight ratio, which saves on materials and the cost of supporting a conventional roof, in the building columns and foundations. Tensile fabric structures are lightweight, flexible and have self-cleaning properties making for easy maintenance, which results in considerable cost savings over conventional structures.

 

Objective:

 

To use fabric roofs on paper machine and ancillary buildings.   

Consideration:

 

For external use there are two main choices of coated fabrics: PVC (Polyvinyl Chloride) coated polyester cloth and PTFE (PolyTetraFluoroEthylene) [Teflon] coated glass cloth, with the latter being the natural choice for permanent structures with a design life over 15 years.

PTFE fiberglass coating is chemically inert, capable of withstanding temperatures from -100F to +450F (-730C to +2320C). The low-surface free energy of the material results in an electrical grade fabric membrane with aninherent non-stick surface, resists pollutant adhesion and allows rain to clean off most dirt.This inertness, thermal stability and surface properties make PTFE-coated fabric membrane ideal for various weather conditions and fire resistance(withstands temperatures up to 1000oC).The anticipated lifespan of the membrane is 25 - 30 years.

 

PTFE's fiberglass yarns maintain ultimate tensile strength of 500,000 PSI and a modulus of elasticity of 10.5 x 106 compared to steel, which offers 29 x 106 PSI. Under normal conditions, the fabric behaves elastically and does not undergo significant stress relaxation or creep.

 

The woven fiberglass gives the PTFE fiberglass membrane its mechanical strength. These filaments, known as beta glass, are the smallest diameter available and provide the membrane with maximum flexibility.

 

The structural design and shape should incorporate the effects of: Wind, Sun, Fire, Thermal Insulation,Snow, condensation, etc.

 

 

Methodology:

 

Reference Information:

1. Birdair Inc. - Tensile Architecture

http://www.birdair.com/tensileArchitecture/default.aspx.

 

 

So, give us your comments by 20 Feb 13, please!

 


Still open for comments CPVC Dryer Bearing Drains (Open until 13 Feb 13)

 

Still open for comments Foundation Design Practice.  (Open until 6 Feb 13)

 

 

And we will be doing something else with the weekly ideas--we will be discussing many of them in a round table discussion at the LGMI Annual Conference January 27 - 29, 2013 here in Atlanta.  You can attend in person for free or online for a nominal costs.  You will need to sign up soon as openings are limited.  Sign up here.

As always, your comments will be appreciated.

 

Think light!

 

 

Brian Brogdon, Ph.D.

 

Executive Director

 

brian.brogdon@gmail.com

 

 

or

 

 

Jim Thompson

 

Founder

 

jthompson@taii.com

 

 

 

 

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Send us your comments!

 

Join Pulp & Paper Radio International for Parts 1 & 2 of Hannu Melarti's Keynote Speech at the Light Green Machine Institute Conference in January 2012.  Just click  HERE.
You will not want to miss the 4th Annual Light Green Machine Conference

January 27 - 29, 2013

Atlanta, Georgia

 

Pre-registration is now Open!  

Sign Up Here

 

 

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Disclaimer

 

LGMI Weekly Ideas are presented for your consideration and inspiration only.  It is solely your responsibility to check for engineering correctness, applicability, standards, insurance policy and local, national or any other legal compliance required before implementing.  Neither The Light Green Machine (TM) Institute, Paperitalo Publications, Talo Analytic International, Inc., nor any individual associated with these entities accepts any responsibility for your application or compliance issues.