Material and flame-retardant principle, pipe and fitting construction, jointing methods, confirmed DN20 dimensions, performance, installation and acceptance notes for aeration, sampling and chemical-duty piping.
← Back to ABS Flame Retardant PipeFlame-retardant ABS pipe is an extruded thermoplastic pipe made from a flame-retardant grade of ABS (acrylonitrile butadiene styrene) resin, supplied together with a matching range of fittings. It is used where a light, corrosion-resistant pipe is needed and where the piping runs through areas in which a standard combustible thermoplastic would not be acceptable. The pipe is red or white, which makes the duty of a line visible at a glance during inspection and maintenance.
The confirmed sizes in our range are red flame-retardant DN20 (outside diameter 25 mm, wall 2.0 mm) and white DN20 (outside diameter 20 mm, wall 1.8 mm). The pipe is supplied per metre, and the matching fittings include clamps, couplings, tees, elbows and caps, so a complete small-bore run can be ordered as one set rather than assembled from several suppliers.
Typical duties are aeration piping, sampling systems, corrosion-resistant piping and drainage or chemical-duty piping in water and wastewater treatment plants, industrial plants and aquaculture installations. Nominal sizes beyond the confirmed DN20 range, other colours and special fitting combinations are produced to order: state the size, the medium and the working pressure on the enquiry and we will confirm availability before quoting.
ABS is a terpolymer of acrylonitrile, butadiene and styrene. The acrylonitrile fraction contributes chemical and heat resistance, the butadiene fraction contributes toughness and impact strength at low temperature, and the styrene fraction gives a rigid, smooth and easily machined surface. The result is a rigid thermoplastic that behaves like a light metal pipe on site, but does not rust and needs no lining, coating or cathodic protection.
Standard ABS is a combustible thermoplastic and would not pass a vertical burn test. A flame-retardant grade is produced by compounding the base resin with a flame-retardant additive system together with stabilisers and processing aids. The additive system works in the solid and gas phases: it raises the temperature at which the material takes part in combustion, promotes the formation of a protective char layer on the burning surface, and dilutes or interrupts the radical chain reaction that sustains the flame. The practical effect is that the material is much harder to ignite, and a flame applied to it does not continue to spread along the surface after the ignition source is removed.
The flammability of a plastics grade is usually described by two numbers. UL 94 is the standard vertical burn classification: a specimen is clamped vertically and a flame is applied to it twice, and the grade is classified by how long it continues to burn, whether it drips and whether the drips ignite cotton below. V-0 is the most demanding of the common vertical ratings, requiring the shortest after-flame and after-glow times and no burning drips; V-1 and V-2 allow progressively more. Limiting oxygen index (LOI) is the minimum oxygen concentration in a nitrogen-oxygen mixture that will just support combustion of the material, measured as a percentage: the higher the figure, the harder the material is to burn. Standard ABS is generally quoted at around 18–19 %, which is close to the 21 % oxygen in air, which is exactly why a normal grade will burn; a flame-retardant compound is formulated to a considerably higher LOI, and that is the property that lets the grade pass a V-0 test.
Flame-retardant ABS compounds are widely available with a UL 94 V-0 rating, and this is the rating usually asked for in an aeration, sampling or chemical-duty piping specification. Our flame-retardant pipe is made from a flame-retardant ABS grade; the flammability rating and the limiting oxygen index of the exact grade supplied are confirmed in writing with the quotation and the material certificate rather than taken from a generic figure, and they are therefore shown as On request below.
Flame retardancy and fire resistance are not the same thing. A flame-retardant pipe does not continue to burn easily, but it is not a fire-rated element and it must not be used to carry out the function of a fire stop, a fire barrier, a fire damper or a fire-resisting penetration seal. Where a penetration has a required fire-resistance period, the fire stopping must be provided by a tested fire-stopping system of its own.
The pipe is a solid-wall extruded tube in uniform lengths with a smooth bore. A solid wall is chosen for this duty because the pipe is small-bore: the wall carries the full pressure on a single homogeneous section, the bore stays smooth for the whole service life with no scale build-up or tuberculation to reduce the flow area, and the pipe can be cut and jointed with ordinary hand tools. One end is formed as a plain end for site fabrication or as a socket for a cemented joint, depending on the jointing method agreed for the project.
The matching fittings are produced from the same flame-retardant material as the pipe, so the whole line behaves the same way in fire and in chemical service and expands and contracts at the same rate. The standard set comprises:
Fittings are confirmed item by item against the order. Send a line list, a sketch or an isometric and we will price the run as a set, which is faster than pricing piece by piece and avoids a shortfall on site.
Red and white are the two colours in this range. Colour is a practical identification aid rather than a decorative choice: in a plant with several small-bore lines on the same wall, the colour of the pipe lets an operator tell one duty from another without tracing it, and it makes an inspection round quicker. The colour of a line should still be recorded on the as-built drawing, because colour codes differ between projects and countries.
| Item | Value |
|---|---|
| Material | ABS — flame-retardant grade |
| Product form | Extruded solid-wall pipe, red and white, with matching fittings |
| Red flame-retardant | DN20, outside diameter 25 mm, wall 2.0 mm |
| White | DN20, outside diameter 20 mm, wall 1.8 mm |
| Fittings | Clamps, couplings, tees, elbows, caps |
| Unit of supply | Per metre, with fittings priced separately |
| Nominal sizes beyond DN20 | On request — state the size required |
| Wall thickness tolerance | On request |
| Pressure rating (working and test) | On request — confirm the working pressure and the required safety factor |
| Standard length per piece | On request |
| Flammability rating (UL 94 class) | On request — confirmed per grade with the material certificate |
| Limiting oxygen index | On request — confirmed per grade |
| Service temperature range | On request — confirm the operating temperature of the line |
| Reference standard | On request — for example ASTM D2661 / D2665, EN 1455, DIN 19531 or your project standard |
| Colour and marking | Red or white as ordered; other colours on request |
| MOQ and price | On request |
Only the confirmed pipe sizes in our current range are published as figures on this page. Dimensions, pressure rating, temperature range and flammability rating are confirmed in writing against the grade and the duty you specify, because a figure that is right for one project standard is not automatically right for another.
ABS does not rust and is not attacked by the dilute acids, alkalis, salt solutions and the general water and wastewater service in which metal pipe corrodes. Because the material is electrically non-conductive and carries no free metal, the line is immune to galvanic corrosion and no lining, coating or cathodic protection is required. As with every thermoplastic, concentrated or strongly oxidising media have to be checked individually against the chemical resistance data for the material before the line is ordered, and aggressive media are confirmed with our team rather than assumed.
ABS is a thermoplastic, so its pressure capability falls as the temperature rises. A pipe that is rated for a given pressure at ambient temperature holds less pressure at elevated temperature, which is why the working pressure and the operating temperature have to be quoted together when the line is sized. The temperature range for the pipe we supply is confirmed on request for the ordered duty.
The grade does not continue to burn after the ignition source is removed, which is the property that makes it acceptable for aeration and sampling piping inside plant buildings and in cable and equipment areas where a standard combustible plastic would not be permitted. See section 2 for the meaning of the UL 94 and oxygen index figures, and for the limit of what a flame-retardant pipe may be used for.
ABS is a smooth, non-porous, non-toxic material that is widely used in potable water, food-service and laboratory piping, and its smooth bore neither supports biofilm growth nor releases material into the water. Where a line carries potable water or comes under a drinking-water regulation, state the requirement on the enquiry: whether the grade we supply carries the particular national approval required for your market is confirmed on request, since approvals differ from country to country.
The pipe is light — roughly one-seventh the density of steel — so it can be handled and carried by one or two people at these diameters, which shortens installation and avoids lifting equipment. ABS keeps good impact strength at low temperature, which is one of the practical reasons it is chosen over rigid PVC in cold service, and it can be cut and machined with ordinary tools.
Like every thermoplastic, ABS expands and contracts more than steel with a change in temperature, so long straight runs are designed with provision for thermal movement and with supports that allow axial movement rather than clamping the pipe rigidly at every point. Prolonged direct sunlight is the other environmental factor to consider for above-ground runs, because long-term UV exposure affects unpainted ABS.
The jointing method is agreed for the project before the pipe is ordered, because the end form of the pipe — plain, socketed or flanged — is set at that point. Tell us the method you intend to use and we will supply the pipe prepared to suit it.
These are general good-practice steps for thermoplastic piping, not a substitute for the installation procedure, test pressure and acceptance criteria in the project specification. Where the two differ, the project specification governs.
To quote accurately and to send the right material, we need the following. The more of it you can send, the faster the quotation and the smaller the risk of a mismatch on site.
Price is on request, so that the quotation reflects the grade, size, fitting list and packing actually ordered rather than a catalogue price for a line item that may not match your specification.
This reference is compiled from the published material data for ABS polymer and flame-retardant ABS compounds, from the standard descriptions of the UL 94 classification and the limiting oxygen index test, and from general good practice for thermoplastic piping in water and wastewater service. Material-family values are given for guidance only. Figures that apply to the pipe we supply — dimensions, pressure rating, temperature range, flammability rating and oxygen index — are issued in writing with the quotation and the material certificate and confirmed against the ordered specification. Where a figure is not confirmed for your duty it is marked On request rather than estimated.