|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: FRP Tanks (LGM 2013.007.01 when issued)
Fiberglass Reinforced Plastics (FRP) or Glass Reinforced Plastics (GRP) is a composite of a polymer: the resin and a ceramic (the glass fibers), used as the construction material for chemical plant equipment like tanks and vessels and are designed for use in several applications, including: acid, alkali and other chemical environments.
To utilize used FRP Tanks (depending on type of application).
The glass fibers provide the strength and stiffness while the thermosetting resin system acts as a binder providing impact resistance, compressive strength and corrosion resistance.
The strength of the FRP product depends on the amount (strength is proportional to the quantity), type and arrangement of glass fiber reinforcement within the polymer.
Depending on the type of application, the thermosetting resin system (epoxy or polyester resins) is chosen for its chemical, mechanical and thermal properties, with epoxy resins used primarily for the manufacture of small diameter piping and polyester resins for larger diameter piping and storage tanks.
FRP tanks and piping offer high resistance to corrosion and temperature in aggressive environments. However consideration towards design, fabrication and installation are required in-order to match the specific application. It is also common for FRP tanks to have a resin-rich inner layer, called a corrosion layer (approximately 100 - 200mm) which offers significant protection against chemical attack from the material being stored inside the vessel. Proper tank handling and installation are extremely important to long term corrosion resistance and low maintenance tank life.
Design Temperature - FRP temperature limits are almost entirely based on the resin: Applications up to 150 degrees F are common and in some cases can reach as high as 300 degrees F. At temperature extremes the thermoplastic resin will suffer from creep and fail.
Design Stresses - Design stresses may vary from 1500psi to 3000psi depending on the type of stress.
Fire Performance - Given the high melting point of the glass reinforcement, FRP tanks are able to maintain its structural integrity when exposed to fire. The glass reinforcement tends to insulate the interior of the product and it is not uncommon for a fire resistant FRP product to be able to withstand a hydrocarbon fire at temperatures up to 1800 degrees F for 30 minutes.
So, give us your comments by 19 March 13, please!
Still open for comments: PVC Air Piping (Open until 12 March 13)
Still open for comments Lightweight aggregate concrete (Open until 5 March 13)
Still open for comments Felted Dryer Drives with integral motor pulleys (Open until 27 Feb 13)
As always, your comments will be appreciated.
Brian Brogdon, Ph.D.
Send us your comments!