Water Tank Glossary

A small opening or pipe fitting on the top of a water tank that allows air to enter and exit as the water level rises and falls. Without an air vent, a vacuum forms inside the tank when water drains, which can cause the tank walls to deform or collapse inward. Air vents are typically fitted with a mesh screen to prevent insects and debris from entering. Required on all sealed water tanks.

Any water storage tank installed on the surface — rooftop, ground level, or on a stand — as opposed to an underground tank. Aboveground polyethylene tanks are the most common type for residential and commercial use in the UAE. Available in vertical and horizontal configurations.

In the context of tank specifications, an aggregated performance score combining wall thickness, material grade, UV resistance, and structural load capacity — used by engineers to compare tank quality across manufacturers.

Weight added to a tank or barrier to prevent it from being moved by wind, water pressure, or accidental impact. Road barriers (such as Alpha Teknik ATI 201/202/203) are filled with water or sand as ballast. Underground tanks must be weighted or anchored to prevent flotation in high water-table areas.

A plastic manufacturing process where a molten tube of plastic (parison) is inflated inside a mould to form hollow containers. Used for smaller polyethylene tanks and containers. Differs from rotational moulding, which is used for large water tanks.

The maximum volume of liquid a tank can hold, measured in litres (L), US gallons (US gal), or cubic metres (m³). Note: actual usable capacity is slightly less than the nominal capacity, as tanks should not be filled to the absolute brim. Conversion: 1 US gallon = 3.785 litres.

The ability of a material to resist deterioration caused by chemical reactions with stored liquids or the surrounding environment. Polyethylene and GRP fiberglass both offer excellent corrosion resistance compared to metal tanks — they do not rust, corrode, or react with most water-based liquids, making them ideal for potable water storage in the UAE.

A curved or saddle-shaped support structure used to hold a horizontal cylindrical tank in a stable, level position. Prevents the tank from rolling and distributes the load evenly. Typically made from steel or heavy-duty plastic. Required for all horizontal tanks installed on ground or vehicle-mounted.

The mass per unit volume of a plastic material, measured in grams per cubic centimetre (g/cm³). Polyethylene density determines its classification:

• LLDPE: 0.915–0.925 g/cm³
• MDPE: 0.926–0.940 g/cm³
• HDPE: 0.941–0.965 g/cm³
• UHMW-HDPE: 0.930–0.935 g/cm³ (different structure)

Higher density generally means greater rigidity and chemical resistance, but lower flexibility.

A fitting located at or near the bottom of a tank that allows it to be completely emptied for cleaning, maintenance, or decommissioning. Also called a drain port or sump drain. A full-bore ball valve is typically installed on the drain fitting for reliable shut-off.

The material (sand, pea gravel, or lean concrete) placed around an underground tank after it is lowered into the excavation pit. Proper embedment supports the tank walls evenly, prevents point loading from rocks or debris, and ensures long-term structural integrity. Sharp fill materials must never be used — they can puncture or stress the tank wall.

An automatic valve connected to the inlet pipe that shuts off the water supply when the tank reaches its maximum fill level. A floating ball rises with the water level and mechanically closes the valve — preventing overflow without electronic controls. Standard in residential and commercial rooftop tanks across the UAE.

A material classification indicating it is safe for contact with food or drinking water — it does not leach harmful chemicals, toxins, or odours into the stored liquid. All Alpha Teknik polyethylene tanks use 100% new virgin polyethylene, which is food-grade and approved for potable water storage by UAE municipalities. Tanks made from recycled plastic are not classified as food-grade.

A pigmented resin layer applied to the outer surface of a GRP fiberglass tank during manufacture. Gelcoat provides a smooth, hard, UV-resistant finish that protects the underlying fiberglass laminate from weathering, chemical attack, and moisture absorption. It also gives GRP tanks their characteristic colour and gloss. A damaged gelcoat surface can be repaired without replacing the entire tank.

Also called fiberglass or FRP (Fibre Reinforced Polymer). A composite material made by embedding glass fibres in a polymer resin matrix (typically polyester or epoxy). GRP combines the strength of glass with the corrosion resistance and light weight of plastic. Key properties:

• High strength-to-weight ratio — stronger than polyethylene at equivalent wall thickness
• Excellent chemical resistance — suitable for a wider range of chemicals than polyethylene
• Large capacity — GRP tanks can be manufactured up to 75,700 L and beyond
• UV resistance — protected by gelcoat outer layer
• Non-corrosive — does not rust or corrode

Alpha Teknik GRP tanks are manufactured from glass fibres, resin, and gelcoat. Available in horizontal, vertical, and underground septic configurations.

A thermoplastic polymer with density 0.941–0.965 g/cm³ — the densest and stiffest grade of standard polyethylene. HDPE offers superior rigidity, tensile strength, and chemical resistance compared to MDPE or LLDPE. Widely used for industrial containers, pipes, IBC frames, and heavy-duty pallets. Recyclable (resin code #2). Not used for rotationally moulded water tanks — that application uses LLDPE for its flexibility during processing.

A water tank where the length axis is horizontal — the tank lies on its side. Horizontal tanks have a lower centre of gravity and a lower profile than vertical tanks of equivalent volume, making them ideal for: vehicle mounting (tanker trucks, farm trailers), tight height-restricted locations, and transport applications. Alpha Teknik horizontal polyethylene tanks are available from 100 to 1,000 US gallons (379–3,800 L).

A reusable industrial container designed for storing and transporting bulk liquids, semi-solids, pastes, and granulated materials. Standard IBC volume is 1,000 litres. Key features:

• Cage frame — steel or plastic outer cage for structural support and forklift handling
• Inner bottle — made from HDPE or (U)HM-HDPE for chemical resistance
• Pallet base — plastic or steel, for forklift and pallet jack access from all four sides
• Stackable — up to two units high when filled
• Bottom valve — 2-inch butterfly or ball valve for dispensing

Alpha Teknik’s IBC tank uses (U)HM-HDPE with UV stabilizer. Priced at AED 1,584 with a 5-year warranty.

The fitting through which water enters the tank from the supply source (mains water, pump, or rainwater). Typically located near the top of the tank. The inlet is connected to the water supply pipe and usually fitted with a float valve to automatically stop filling when the tank is full. Standard inlet sizes are ½ inch, ¾ inch, or 1 inch BSP depending on tank capacity.

In GRP construction, the laminate is the structural body of the tank — built up from alternating layers of glass fibre (woven mat or chopped strand mat) and resin. The thickness and fibre orientation of the laminate determines the tank’s strength, pressure rating, and chemical resistance. More laminate layers = stronger, heavier tank. The laminate is protected externally by the gelcoat and internally by a resin-rich liner.

A flexible, tough form of polyethylene with density 0.915–0.925 g/cm³. LLDPE has a linear molecular structure with short-chain branches, giving it higher tensile strength and puncture resistance than LDPE while remaining flexible. It is the primary material used in rotationally moulded water tanks — including all Alpha Teknik polyethylene tanks — because it flows smoothly inside the mould at high temperatures and forms a uniform, stress-free wall. Key properties:

• Excellent impact resistance, especially at low temperatures
• Good chemical resistance to water, dilute acids, and alkalis
• Food-grade when manufactured from virgin resin
• UV stabilizers can be compounded in during manufacture

A large access opening (typically 400–600 mm diameter) on the top of a tank, sealed with a removable cover or hatch. Manholes allow a person or equipment to physically enter the tank for inspection, cleaning, or repair. Required on large industrial tanks. On smaller residential tanks, a lid or inspection port serves this purpose.

A thermoplastic polymer with density 0.926–0.940 g/cm³ — between LLDPE and HDPE. MDPE balances flexibility and rigidity, offering excellent stress-crack resistance and good chemical resistance. Common applications:

• Gas and water pipe systems — PE 80 and PE 100 grade pipes
• Blow-moulded containers — drums and bottles
• Plastic compound raw material — base resin for compounding

Alpha Teknik supplies ALPHA Smart Polyethylene Compound (MDPE) at AED 159/unit for plastic manufacturers in the UAE.

The fitting through which water exits the tank to supply the building or system. Usually located near the bottom of the tank to allow maximum use of stored water. Connected to the distribution pipe and fitted with a shut-off valve (typically a ball valve or gate valve). The outlet fitting size matches the distribution pipe — common sizes are ¾ inch, 1 inch, or 1½ inch BSP.

A fitting positioned just below the tank’s maximum water level that allows excess water to drain away safely if the float valve fails or water pressure is higher than expected. The overflow pipe directs water to a safe discharge point — typically a drain, gutter, or soakaway — preventing water damage from an overfilled tank. The overflow diameter must be larger than the inlet to ensure it can clear water faster than it enters. A backup safety feature on all properly installed tanks.

The world’s most widely used thermoplastic polymer, produced by polymerising ethylene (C₂H₄). Polyethylene is classified by density into LLDPE, MDPE, HDPE, and UHMW-HDPE — each with different mechanical and chemical properties. All Alpha Teknik water tanks are manufactured from 100% new virgin polyethylene with UV stabilizers, produced in Dubai, UAE. Key advantages for water storage:

• Inert — does not corrode, rust, or leach chemicals into water
• Food-grade (when virgin resin is used)
• Lightweight and impact-resistant
• Can be compounded with UV stabilizers for outdoor use
• Seam-free when rotationally moulded — no joints to leak

Water that is safe for human consumption — drinking, cooking, and personal hygiene. Potable water storage tanks must be made from food-grade materials that do not leach harmful substances. All Alpha Teknik polyethylene tanks are approved for potable water storage by UAE municipalities. Tanks made from recycled plastic are not suitable for potable water.

The polymer matrix material in a GRP composite — it surrounds and bonds the glass fibres, transferring loads between fibres and protecting them from the environment. Common resin types for GRP tanks:

• Isophthalic polyester resin — good chemical resistance and water resistance; standard for water tanks
• Orthophthalic polyester resin — lower cost, adequate for non-aggressive media
• Vinyl ester resin — highest chemical resistance; used for aggressive chemical storage
• Epoxy resin — excellent chemical resistance and structural properties; higher cost

The manufacturing process used to produce all Alpha Teknik polyethylene water tanks. A pre-measured charge of powdered polyethylene resin is placed inside a hollow mould. The mould is heated in an oven while rotating simultaneously on two perpendicular axes — the melted plastic coats the entire inner surface evenly. The mould is then cooled and opened to release the finished tank. Key advantages:

• Seamless, one-piece construction — no weld lines or joints to fail
• Uniform wall thickness throughout the tank
• Low tooling cost — economical for large tanks
• Complex shapes possible — vertical, horizontal, underground, and custom profiles
• Multiple layers — 3, 4, or 5 layers can be created in one process for UV and thermal insulation

An underground tank used for the primary treatment of sewage and wastewater where connection to a municipal sewer system is unavailable. Solid waste settles to the bottom (sludge), while liquid effluent flows out to a soakaway or secondary treatment. Alpha Teknik GRP underground septic tanks are available from 300 to 20,000 US gallons (1,140–75,700 L), priced from AED 1,515. Commonly used at remote construction camps, farms, and villas in the UAE.

A vertical polyethylene tank with a wider diameter and shorter height than a standard vertical tank of the same capacity. Designed specifically for low-clearance rooftops where parapet walls or structural constraints limit the maximum tank height. Alpha Teknik offers short-profile tanks in 500 US gal (1,900 L) and 1,000 US gal (3,800 L).

The ratio of a material’s density to the density of water (1.0 g/cm³). All polyethylene grades have a specific gravity less than 1.0 — meaning they float on water. This is relevant when sizing underground tank anchoring systems in high-water-table areas, where an empty polyethylene tank can be pushed upward by groundwater pressure (buoyancy). Concrete ballast or anchor straps are used to prevent flotation.

A threaded insert moulded into the tank wall during manufacture, allowing pipes, valves, and accessories to be connected. Tank fittings are typically made from polypropylene (PP) or HDPE and are available in BSP (British Standard Pipe) thread sizes. Common fitting positions: top (inlet, air vent, overflow), side (outlet), bottom (drain). Fittings must be compatible with the stored liquid — check chemical resistance before installing non-standard fittings.

A polymer that softens and can be reshaped when heated, then hardens again when cooled — a reversible process. All polyethylene grades (LLDPE, MDPE, HDPE) are thermoplastics. This property enables rotational moulding, injection moulding, and extrusion manufacturing processes. Thermoplastics are generally recyclable. Contrasts with thermosets (such as the resin in GRP), which cure permanently and cannot be remelted.

An extreme-performance grade of polyethylene with a very long polymer chain (molecular weight 3.5–7.5 million g/mol), giving it exceptional abrasion resistance, impact resistance, and chemical resistance — the highest of any thermoplastic. Used in Alpha Teknik IBC tanks for its ability to store a wide range of chemicals without degradation. Also used in: wear liners, conveyor parts, bulletproof panels, and medical implants.

A tank designed to be buried below ground level. Underground tanks must be structurally engineered to resist external soil pressure, groundwater pressure, and vehicle loads above (if installed beneath a road or driveway). Alpha Teknik offers polyethylene underground tanks (500–1,000 US gal, 10-year warranty) and GRP underground septic tanks (300–20,000 US gal). Underground tanks must be installed on a level sand or concrete base with appropriate backfill material.

A chemical additive compounded into polyethylene resin during manufacture to protect the plastic from degradation caused by ultraviolet (UV) radiation from sunlight. Without UV stabilizers, polyethylene becomes brittle, discolours, and develops surface cracks within 1–2 years of outdoor exposure — especially critical in the UAE where UV intensity is extreme. UV stabilizers (typically HALS — Hindered Amine Light Stabilizers) absorb or neutralise UV energy before it damages the polymer chain. All Alpha Teknik polyethylene tanks include UV stabilizers formulated for UAE climate conditions.

A water tank where the central axis is vertical — the tank stands upright. The most common configuration for rooftop and ground-level water storage in the UAE. Vertical tanks have a smaller footprint than horizontal tanks of equivalent volume and are better suited for gravity-fed distribution systems (water flows down by gravity from a rooftop tank). Alpha Teknik vertical polyethylene tanks range from 50 to 5,000 US gallons (190–19,000 L).

Polyethylene resin that has never been processed or used before — produced directly from raw petrochemical feedstock with no recycled content. Virgin resin has consistent and predictable mechanical properties, is food-grade safe, and meets potable water standards. All Alpha Teknik tanks are made from 100% new virgin polyethylene — never recycled material. This is critical for water quality, tank longevity, and regulatory compliance. Tanks using recycled polyethylene may contain contaminants and cannot be guaranteed food-safe.

The thickness of the tank wall, typically measured in millimetres. Greater wall thickness provides higher structural strength, better thermal insulation, and improved UV resistance. In multi-layer tanks, total wall thickness is the sum of all layers. A thicker wall also means a heavier, more expensive tank. Alpha Teknik’s 5-layer tanks have the greatest total wall thickness and carry the longest warranty (10 years).

The level below ground at which soil is saturated with water. When underground tanks are installed in areas with a high water table, the groundwater can exert upward pressure (buoyancy) on an empty or partially filled tank — potentially lifting it out of the ground. Underground tanks in high-water-table locations must be anchored with concrete slabs, straps, or by keeping them filled at all times. A geotechnical site assessment is recommended before installing large underground tanks in UAE coastal or low-lying areas.

Polyethylene water tanks manufactured with multiple distinct layers in a single rotational moulding cycle. Each layer serves a purpose:

• Inner layer — food-grade virgin polyethylene in contact with stored water
• Middle layer(s) — structural core; may include a foam insulation layer to reduce heat gain
• Outer layer — UV-stabilised polyethylene to resist sunlight degradation