FRP tanks and vessels
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FRP ( Fibreglass Reinforced Plastics, also known as GRP, or Glass Reinforced Plastics) is a modern
composite material A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...
of construction for chemical plant equipment like
tank A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engin ...
s and vessels. Chemical equipment that range in size from less than a metre to 20 metres are fabricated using FRP as material of construction. FRP Chemical Equipments are manufactured mainly by Hand Lay-up and
filament winding Filament winding is a fabrication technique mainly used for manufacturing open (cylinders) or closed end structures (pressure vessels or tanks). This process involves winding filaments under tension over a rotating mandrel. The mandrel rotates aro ...
processes.
BS4994 BS4994 (formally: British Standard 4994:1987) is the "specification for the design and construction of vessels and storage tanks in reinforced plastics". It specifies a code of practice for use by manufacturers of such containers. With the publicat ...
still remains a key standard for this class of items.


Dual Laminate

Due to the
corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...
resistant nature of FRP, the tank can be made entirely from the composite, or a second liner can be used. In either case, the inner liner is made using different material
properties Property is the ownership of land, resources, improvements or other tangible objects, or intellectual property. Property may also refer to: Mathematics * Property (mathematics) Philosophy and science * Property (philosophy), in philosophy and ...
than the structural portion (Hence the name dual (meaning two) and laminate (a word commonly used for a layer of a composite material)) The liner, if made of FRP is usually resin rich and utilizes a different type of
glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...
, called "C-Glass", while the structural portion uses "E-Glass". The thermoplastic liner is usually 2.3 mm thick (100 mils). This thermoplastic liner is not considered to contribute mechanical strength. The FRP liner is usually cured before winding or lay-up continues, by using either a BPO/ DMA system, or using an
MEKP Methyl ethyl ketone peroxide (MEKP) is an organic peroxide with the formula CH3)(C2H5)C(O2H)sub>2O2. MEKP is a colorless oily liquid. It is widely used in vulcanization (crosslinking) of polymers. It is derived from the reaction of methyl ethy ...
catalyst with
cobalt Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, pr ...
in the
resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on natu ...
. If the liner is not made of FRP, there are multiple choices for a thermoplastic liner. The
engineer Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the l ...
will need to design the tank based on the chemical corrosion requirement of the equipment. PP, PVC,
PTFE Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemour ...
,
ECTFE ECTFE (ethylenechlorotrifluoroethylene) is a copolymer of ethylene and chlorotrifluoroethylene. It is a semi-crystalline fluoropolymer (a partially fluorinated polymer) designed to provide chemical resistance in heavy-duty corrosion application ...
,
ETFE Ethylene tetrafluoroethylene (ETFE) is a fluorine-based plastic. It was designed to have high corrosion resistance and strength over a wide temperature range. ETFE is a polymer and its source-based name is poly(ethene-co-tetrafluoroethene). It i ...
, FEP,
CPVC Chlorinated polyvinyl chloride (CPVC) is a thermoplastic produced by chlorination of polyvinyl chloride (PVC) resin. CPVC is significantly more flexible than PVC, and can also withstand higher temperatures. Uses include hot and cold water deli ...
,
PVDF Polyvinylidene fluoride or polyvinylidene difluoride (PVDF) is a highly non-reactive thermoplastic fluoropolymer produced by the polymerization of vinylidene difluoride. PVDF is a specialty plastic used in applications requiring the highest pur ...
are used as common thermoplastic liners. Due to FRP's weakness to
buckling In structural engineering, buckling is the sudden change in shape (deformation) of a structural component under load, such as the bowing of a column under compression or the wrinkling of a plate under shear. If a structure is subjected to a gr ...
, but immense strength against
tensile In physics, tension is described as the pulling force transmitted axially by the means of a string, a rope, chain, or similar object, or by each end of a rod, truss member, or similar three-dimensional object; tension might also be described as t ...
forces and its resistance to corrosion, a
hydrostatic Fluid statics or hydrostatics is the branch of fluid mechanics that studies the condition of the equilibrium of a floating body and submerged body "fluids at hydrostatic equilibrium and the pressure in a fluid, or exerted by a fluid, on an imme ...
tank A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engin ...
is a logical application for the composite. The tank is designed to withstand the hydrostatic forces required by orienting the
fibre Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...
s in the tangential direction. This increases the hoop strength, making the tanks
anisotropic Anisotropy () is the property of a material which allows it to change or assume different properties in different directions, as opposed to isotropy. It can be defined as a difference, when measured along different axes, in a material's physic ...
ally stronger than steel (pound per pound). FRP which is constructed over the liner provides the structural strength requirements to withstand design conditions such as internal
pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...
or
vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often dis ...
, hydrostatic loads,
seismic Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other ...
loads (including fluid sloshing),
wind Wind is the natural movement of air or other gases relative to a planet's surface. Winds occur on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few hou ...
loads, regeneration hydrostatic loads, and even
snow Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout ...
loads.


Applications

FRP tanks and vessels designed as per
BS 4994 BS4994 (formally: British Standard 4994:1987) is the "specification for the design and construction of vessels and storage tanks in reinforced plastics". It specifies a code of practice for use by manufacturers of such containers. With the publicat ...
are widely used in the chemical industry in the following sectors: chlor-alkali manufacturers, fertilizer, wood pulp and paper, metal extraction,
refining {{Unreferenced, date=December 2009 Refining (also perhaps called by the mathematical term affining) is the process of purification of a (1) substance or a (2) form. The term is usually used of a natural resource that is almost in a usable form, b ...
,
electroplating Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the reduction of cations of that metal by means of a direct electric current. The part to be ...
,
brine Brine is a high-concentration solution of salt (NaCl) in water (H2O). In diverse contexts, ''brine'' may refer to the salt solutions ranging from about 3.5% (a typical concentration of seawater, on the lower end of that of solutions used for br ...
,
vinegar Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. Vinegar typically contains 5–8% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation, converting simple sugars to et ...
,
food processing Food processing is the transformation of agricultural products into food, or of one form of food into other forms. Food processing includes many forms of processing foods, from grinding grain to make raw flour to home cooking to complex industr ...
, and in air pollution control equipment, especially at
municipal A municipality is usually a single administrative division having corporate status and powers of self-government or jurisdiction as granted by national and regional laws to which it is subordinate. The term ''municipality'' may also mean the go ...
waste water treatment plants Sewage treatment (or domestic wastewater treatment, municipal wastewater treatment) is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable for discharge to the surrounding envir ...
and
water treatment plants Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, inclu ...
.


Types

FRP tanks and process vessels are used in various commercial and industrial applications, including chemical, water & wastewater, food & beverage, mining & metals, power, energy, and high-purity applications.


Scrubbers

FRP
Scrubber Scrubber systems (e.g. chemical scrubbers, gas scrubbers) are a diverse group of air pollution control devices that can be used to remove some particulates and/or gases from industrial exhaust streams. An early application of a carbon dioxide scr ...
s are used for scrubbing
fluids In physics, a fluid is a liquid, gas, or other material that continuously deforms (''flows'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear ...
. In air pollution control technology, scrubbers come in three varieties, Dry Media, Wet Media, and Biological.


Dry Media

Dry media typically involved a dry, solid media (such as
activated carbon Activated carbon, also called activated charcoal, is a form of carbon commonly used to filter contaminants from water and air, among many other uses. It is processed (activated) to have small, low-volume pores that increase the surface area avail ...
) suspended in the middle of the vessel on a system of
beam Beam may refer to: Streams of particles or energy *Light beam, or beam of light, a directional projection of light energy **Laser beam *Particle beam, a stream of charged or neutral particles **Charged particle beam, a spatially localized grou ...
supports and grating. The media controls the
concentration In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', ''molar concentration'', ''number concentration'', an ...
of a
pollutant A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. These can be both naturally forming (i.e. minerals or extracted compounds like oi ...
in the incoming gas via
adsorption Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the ''adsorbate'' on the surface of the ''adsorbent''. This process differs from absorption, in which a f ...
and
absorption Absorption may refer to: Chemistry and biology * Absorption (biology), digestion **Absorption (small intestine) *Absorption (chemistry), diffusion of particles of gas or liquid into liquid or solid materials *Absorption (skin), a route by which ...
. These vessels have several design constraints. They must be designed for *Unloading and Reloading the media *Corrosive effects of the fluid to be treated *Internal and External Pressure *Environmental Loads *Support Loads for the grating and support system *Lifting and Installing the Vessel *Regenerating the media inside the vessel *Internal Stack supports for a dual bed construction *Redundancy for preventative maintenance *Demisting to remove liquids that degrade the dry media *Condensate removal, to remove any liquid that
condense Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor to ...
s inside the vessel


Wet media

Wet media scrubbers typically douse the polluted fluid in a scrubbing solution. These vessels must be designed to more stringent criteria. The design constraints for wet media scrubbers typically include: *The corrosive effects of the polluted fluid and the scrubbing solution. *The high pressures and loading of a spray system *Aerodynamics of the internal media to ensure that there is no bypass *Internal Support systems *Reservoir of scrubbing fluid for recirculation. *Internal and External Pressure *Environmental Loads *Lifting and Installing the vessel *Plumbing of the scrubbing fluid to the vessel *Draining to remove vessel sump fluids In the case of a ''decarbonator'', used in
reverse osmosis Reverse osmosis (RO) is a water purification process that uses a partially permeable membrane to separate ions, unwanted molecules and larger particles from drinking water. In reverse osmosis, an applied pressure is used to overcome osmotic pre ...
systems to limit the concentration of gases in the water, the air is the scrubbing fluid and the sprayed liquid is the polluted stream. As the water is sprayed out of the scrubber, the air strips the aqueous gasses out of the water, to be treated in another vessel.


Biological

Biological scrubbers are structurally identical to the wet media scrubbers, but vary in their design. The vessel is designed to be larger, so the air moves slower through the vessel. The media is designed to encourage biological growth, and the water that sprays through the vessel is filled with
nutrients A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...
to encourage
bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
to grow. In such scrubbers, the bacteria scrub the pollutant. Also, instead of a single, large support system (typically 10 feet depth of media for chemical scrubbers), there are multiple stages of media support, that can change the design requirements of the vessel. (See
biofilter Biofiltration is a pollution control technique using a bioreactor containing living material to capture and biologically degrade pollutants. Common uses include processing waste water, capturing harmful chemicals or silt from surface runoff, and ...
for similar technology that is usually performed outside of an FRP vessel.)


Tanks

A typical storage tank made of FRP has an inlet, an outlet, a vent, an access port, a drain, and an overflow nozzle. However, there are other features that can be included in the tank.
Ladders A ladder is a vertical or inclined set of rungs or steps used for climbing or descending. There are two types: rigid ladders that are self-supporting or that may be leaned against a vertical surface such as a wall, and rollable ladders, such ...
on the outside allow for easy access to the roof for loading. The vessel must be designed to withstand the load of someone standing on these ladders, and even withstand a person standing on the roof. Sloped bottoms allow for easier draining. Level gauges allow someone to accurately read the liquid level in the tank. The vessel must be resistant to the corrosive nature of the fluid it contains. Typically, these vessels have a secondary containment structure, in case the vessel bursts.


Size

The size of FRP Vessels is rarely limited by
manufacturing Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of secondary sector of the economy. The term may refer to a r ...
technology, but rather by
economics Economics () is the social science that studies the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods and services. Economics focuses on the behaviour and intera ...
. Tanks smaller than 7,500
liter The litre (international spelling) or liter (American English spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic centimetres (cm3) or 0.001 cubic metre (m3). ...
s (2,000
gallons The gallon is a unit of volume in imperial units and United States customary units. Three different versions are in current use: *the imperial gallon (imp gal), defined as , which is or was used in the United Kingdom, Ireland, Canada, Austral ...
) are easily manufactured out of cheaper materials, such as
HDPE High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a thermoplastic polymer produced from the monomer ethylene. It is sometimes called "alkathene" or "polythene" when used for HDPE pipes. With a high strength-to-density ratio, ...
or PVC. Tanks larger than four meters are generally limited by
shipping Freight transport, also referred as ''Freight Forwarding'', is the physical process of transporting Commodity, commodities and merchandise goods and cargo. The term shipping originally referred to transport by sea but in American English, it h ...
constraints, and the economics suggest a
concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wi ...
or
steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...
tank fabricated at the tank's
location In geography, location or place are used to denote a region (point, line, or area) on Earth's surface or elsewhere. The term ''location'' generally implies a higher degree of certainty than ''place'', the latter often indicating an entity with an ...
. For
chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wi ...
storage and
air pollution control Emission standards are the legal requirements governing air pollutants released into the atmosphere. Emission standards set quantitative limits on the permissible amount of specific air pollutants that may be released from specific sources ove ...
, the choice is to make multiple tanks of smaller
diameters In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid fo ...
. For example, one of the largest odor control projects in
California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
, the
Orange County Orange County most commonly refers to: *Orange County, California, part of the Los Angeles metropolitan area Orange County may also refer to: U.S. counties *Orange County, Florida, containing Orlando *Orange County, Indiana *Orange County, New ...
Sanitation District will utilize 24 vessels total to treat 188,300 cfm (86,200 L/s) of odorous air, with a design of up to 50 ppm of
hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The unde ...
. For an equivalent single vessel to perform as well as the 13 headworks
trickling filter A trickling filter is a type of wastewater treatment system. It consists of a fixed bed of rocks, coke, gravel, slag, polyurethane foam, sphagnum peat moss, ceramic, or plastic media over which sewage or other wastewater flows downward and ca ...
s, the single vessel would have to be over 36 feet in diameter. This would be impractical due to the high shipping requirements, internal supports,
spray nozzle A spray nozzle is a device that facilitates the dispersion of a liquid by the formation of a spray. The production of a spray requires the fragmentation of liquid structures, such as liquid sheets or ligaments, into droplets, often by using k ...
s and other internals. Plus this single vessel would not incorporate redundancy for
preventive maintenance The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure, and supporting utilities in industrial, business, and residential installa ...
.


Limitations

Typical FRP vessels and constructs limits are almost entirely based on the application parameters and resins used. The thermoplastic resin will suffer from creep at elevated temperatures and ultimately fail. However, new
chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...
has produced resins that claim to be able to achieve even higher temperatures, which expand this field immensely. The typical maximum is 200 degrees Celsius. Fiberglass vessels and constructs are also susceptible to degradation upon long-term exposure to sunlight. This deterioration is brought about by chemical changes which occur as a result of exposure to the ultraviolet (UV) portion of light. Degradation results in the fiberglass tanks and constructs, opening pores in the surface allowing styrene to wick out of the vessel or construct's walls, causing them to become embrittled, reducing the impact resistance and potential elongation properties of the part. Degradation from UV light can be effectively inhibited by the addition of exterior gelcoats and sealants, which protect the fiberglass construct through removing UV access to the product's surface thus deflecting UV energy. The UV life of a part is dependent upon UV additive level and type as well as part thickness and design, pigment type, level and effectiveness of dispersion, processing conditions and the geographic location where the molded part is used (see Figure 3). It is important when comparing resin UV performance to ensure that the testing has been done on a consistent basis. In Figure 1, accelerated weathering data is presented. Generally, 2,000 hours corresponds to 1 year in Florida and 1,400 hours to 1 year in Southern Canada. Often terms like “UV-8” are used. UV-8 means the material can withstand 8,000 hours in a Xenon Ci-65 weatherometer. UV-2 or UV-4 would mean 2,000 or 4,000 hours respectively. Hence, UV-8 corresponds to approximately 4 years of continuous outdoor exposure in Florida. It is important to understand which weatherometer, i.e. Carbon Arc or Xenon, was used, as well as the details of how the weatherometer was run. ASTM D-2565 is the recognized standard. Testing can be performed using actual outdoor weathering exposure, such as Florida and Arizona, to confirm this data. Note Figure 1 uses the industry standard criteria of when the sample has reached less than 50% of its original break elongation to determine the end of the test. In most cases useful life of the part extends beyond this point. All samples in Figure 1 are nonpigmented as supplied by Exxon Chemical. The UV performance test data can be found on our data sheets for each specific grade. Light Stability Characteristics Ultraviolet (UV) Stabilization Plastics are attacked and deteriorate when exposed to direct sunlight. When plastic tanks absorb the sun's ultraviolet light, the UV energy excites the polymers’chains, causing them to break. The effects are discoloration, embrittlement and eventual cracking. Elevated temperatures and oxygen tend to accelerate the deterioration. Tanks listed as suitable for outdoor service are protected from UV attack by: coloring or pigmenting and/or adding internal stabilizers which preferentially absorb or dissipate the UV energy. Shading tanks from the sun will also prevent deterioration. Tanks must be free to expand or contract, avoid excessive tension on the tank. For assistance in selecting the appropriate tank for a specific application, see the Tank Resin Selector Guides with reputable resin manufacturers. Resources being published by Raventank.com siting additional references to AVENGENERAL ISOLINES OF GLOBAL RADIATION AND THERE EFFECTS ON POLYMERS Years = 70 x UV Rating (Your Location's Isoline) (from Figure 3) Example: Natural Part, Molded Properly, Using UV-8 Additive Package For Use in Florida i.e.Florida= 140 Kcal/cm@2/yr. (from Figure 3) Thus Years “Expected”= 70/140 x 8 = 4 Years (until 50% of original break elongation properties left. Think of protecting your fiberglass investments from UV, much the same way you would protect your children with sun screen; gelcoats are sunscreens for your tanks, vessels and other fiberglass constructs.


Design standards

Fiberglass Tanks fall under regulation of several groups. *
Bs4994 BS4994 (formally: British Standard 4994:1987) is the "specification for the design and construction of vessels and storage tanks in reinforced plastics". It specifies a code of practice for use by manufacturers of such containers. With the publicat ...
-87 is the
British Standards British Standards (BS) are the standards produced by the BSI Group which is incorporated under a royal charter and which is formally designated as the Standards organization#National standards bodies, national standards body (NSB) for the UK. The ...
Standard for FRP Tanks and Vessels superseded by EN 13121. *EN 13121 *
ASME The American Society of Mechanical Engineers (ASME) is an American professional association that, in its own words, "promotes the art, science, and practice of multidisciplinary engineering and allied sciences around the globe" via "continuing ...
RTP-1 (Reinforced Thermoset Plastic Corrosion Resistant Equipment) is the standard for FRP tanks and vessels held within the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
under 15
psig The pound per square inch or, more accurately, pound-force per square inch (symbol: lbf/in2; abbreviation: psi) is a unit of pressure or of stress based on avoirdupois units. It is the pressure resulting from a force of one pound-force applied to ...
and located partially or fully above ground. Typical
design A design is a plan or specification for the construction of an object or system or for the implementation of an activity or process or the result of that plan or specification in the form of a prototype, product, or process. The verb ''to design'' ...
parameters and specifications will require either compliance with ASME RTP-1 or accreditation from ASME. *
ASTM ASTM International, formerly known as American Society for Testing and Materials, is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, an ...
3299 which is only a product specification, governs the filament winding process for tanks. It is not a design standard. * SS245:1995 Singapore Standard for Sectional GRP Water Storage Tanks.


Bs4994

It is to avoid the uncertainty associated with specifying the thickness alone, that BS4994 introduced the concept of "unit properties". It is property per unit width, per unit mass of reinforcement. For example, UNIT STRENGTH is defined as load in Newton per millimeter (of laminate width) for a layer consisting of 1 kg of glass per square meter. i.e. the unit is N/mm per Kg/m2 glass


ASME RTP-1

In RTP-1 specifications, the primary concerns relate
stress Stress may refer to: Science and medicine * Stress (biology), an organism's response to a stressor such as an environmental condition * Stress (linguistics), relative emphasis or prominence given to a syllable in a word, or to a word in a phrase ...
and
strain Strain may refer to: Science and technology * Strain (biology), variants of plants, viruses or bacteria; or an inbred animal used for experimental purposes * Strain (chemistry), a chemical stress of a molecule * Strain (injury), an injury to a mu ...
, such as hoop stress, axial stress, and breaking stress to the physical properties of the material, such as
Young's modulus Young's modulus E, the Young modulus, or the modulus of elasticity in tension or compression (i.e., negative tension), is a mechanical property that measures the tensile or compressive stiffness of a solid material when the force is applied leng ...
(which may require an anisotropic analysis due to the filament winding process). These are related to the loads of the design, such as the internal
pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...
and strain.


BS EN 13121

This European standard replaces BS4994-87 which is marked now as Current, Obsolescent, Superseded.


SS245:1995

This is the Singapore Standard for sectional GRP water tank, which is current.


Manufactures


Mitsubishi Chemical Infratec


See also

* BS EN 13121-3 *
BS 4994 BS4994 (formally: British Standard 4994:1987) is the "specification for the design and construction of vessels and storage tanks in reinforced plastics". It specifies a code of practice for use by manufacturers of such containers. With the publicat ...


References

Example of a GRP Sectional tank. https://www.mechgroup.co.uk/grp-sectional-tanks Example of GRP Cylindrical tanks. https://www.mechgroup.co.uk/grp-cylindrical-tanks


Further reading

* * — a case study of the design process of a cylindrical vessel, using the BS 4994 methodology
FRP Tanks and Vessels manufacturing
* {{cite web , url = https://coventivecomposites.com/explainers/grp-tank-covers-how-to-meet-regulatory-requirements-in-a-cost-effective-way/ , title = GRP Tank Covers: How to meet regulatory requirements in a cost-effective way , publisher = Coventive Composites — GRP Tank Covers: How to meet regulatory requirements in a cost-effective way Storage tanks Sewerage Containers Scrubbers