Fibreglass vs. Rotationally Moulded Polyethylene Tanks For Chemical Storage Applications

Chemical tanks can be had in fibreglass or polyethylene tanks (as well as stainless steel); this article discusses the differences and where one may be better than the other (click on the source link for an in depth discussion of the various properties of both fibreglass chemical tanks and polyethylene chemical tanks.

Storage tanks used in the chemical industry come in a variety of models, types of materials. Two of the most common are fiberglass tanks (FRP) and polyethylene (PE) tanks. These two materials offer unique advantages for a wide range of chemical  applications. When evaluating the tank design and material it is important to review the chemical compatibility, impact resistance, weatherability, overall cost, temperature, performance, vacuum or pressure requirement, stress crack resistance, environmental  friendliness, etc.  In light of the wide diversity of performance characteristics, a comparative study of the benefits and features of each of these materials, especially in the storage of harsh chemicals, is appropriate.

Materials

The resin or tank material is a critical part of the tank design. The decision as to what material the tank is to be made of is determined by the actual application. When considering a polyethylene tank you have two families of resins. Rotationally moulded tanks will be manufactured with either high density cross-linked (XLPE) or linear polyethylene. The cross-linked family of resins is limited to one cross-linked resin for
rotational molding where the linear family of resins is available in low (LLDPE), medium (MDLPE) and high (HDLPE) density versions. The choice of the resin should be based upon the application and recommendations of the tank manufacturer. When you consider a fiberglass (FRP) tank there are more resins and combinations of materials to consider. Polyethylene tanks are made up of one material. FRP tanks are a
combination of materials in the laminate. A FRP tank will have a extensive offering of resin grades and types, pigments, fillers, resin cure systems, post cure requirements, inner corrosion barrier, interior layers, interior secondary layers, interior top coat, surface  veil, reinforcement, sizing of reinforcement, percentage of reinforcement and the laminate construction (inner surface, interior layer, and structural layer). Referring to a tank as fiberglass or FRP is like referring to a tank as plastic. There are numerous materials that can be called plastic and there are numerous combinations of materials and designs that are categorized as fiberglass (FRP). Fiberglass tank fabrication tends to have more potential for human error. The manufacturer’s expertise, consistency, quality assurance and qualified equipment are critical when specifying fiberglass and rotationally molded polyethylene tanks. The cross-linked and the linear polyethylene resins have applications where they will both work. The high density linear (HDLPE) resin is utilized in the majority of the applications where both resins will work. The high density linear resin (HDLPE) is capable of meeting the requirements for FDA & NSF materials. The HDLPE resin is a repairable material by welding and it is a recyclable material. The cross-linked resin will be the resin of choice for applications such as polymers and surfactants.
Note: HDPE is a generic term which relates to both the cross-linked polyethylene and the linear polyethylene. HDPE stands for high density polyethylene. The cross-linked is only available in a high density version where the linear resins for rotational molding are available in low, medium and high density versions. When specifying resins it is important to consider the actual density of the resin to make sure that the correct resin choice is being made. Do not be fooled by manufacturers that reference all of their resins as HDPE.

Source: Snyder Industries Tanks (read more about chemical resistance, mechanical properties, design flexibility, weatherability and manufacturing reliability of both fibreglass tanks and poly tanks by clicking here).

JoJo Tanks in South Africa manufacture high quality polyethylene chemical tanks in both medium duty (SG 1.4) and heavy duty (SG 1.6) and are suitable for storing a long list of chemicals. Poly chemical tanks are less expensive than stainless steel chemical tanks and in many cases are superior when it comes to corrosion resistance to certain chemicals. Click on the links below to view more JoJo Tanks products, including water tanks, chemical tanks, septic tanks, underground tanks, silo tanks, silo tank stands, water tank stands and more.

JoJo Tanks South Africa offer a wide range of products such as plastic water tanks and chemical tanks to suit every household, business or agricultural need, including silo tanks and silo tank stands as well as other high quality JoJo Tanks products.  See JoJo Tanks’ VERTICAL TANKS, HORIZONTAL TANKS (transporter tanks), STEEL TANK STANDS and OTHER JOJO PRODUCTS and see JoJo Tanks’ NEW 6000 LITRE UNDERGROUND TANKS. Also see our FAQ and WATER TANK PRICES.