Airports in Uzbekistan are being built and expanded: new terminals, hangars, cargo and fuel facilities. Almost all of this is a steel frame with large spans, and almost always the design requires its fire resistance to be brought up to the code level with a fire-protective coating. Below is what exactly the design specifies, how an airport differs from an ordinary warehouse, and what the client should check before work starts.

The R rating is set by the building’s degree of fire resistance

The required fire resistance rating of steel structures is assigned not by the contractor or the paint manufacturer but by the designer, based on the building’s degree of fire resistance. In Uzbekistan, the relationship between the degree of fire resistance and the ratings for each type of structure is set by Table 4 of ShNK 2.01.02-04 “Fire Safety of Buildings and Structures”. For a steel frame, two of its columns matter: load-bearing elements and elements of roofs without an attic (trusses, beams, purlins):

Degree I — load-bearing elements R 120, roof trusses, beams and purlins R 30;
Degree II — load-bearing elements R 90, roof elements R 15;
Degree III — load-bearing elements R 45, roof elements R 15;
Degree IV — R 15 for both groups.

Hence the typical picture in terminal calculations: columns and bracing of the main frame at R 120 or R 90, roof trusses and purlins at R 30 or R 15. Where the code requires R 15, ShNK allows the steel to be left unprotected, except where the element’s actual rating, by testing or calculation, is below R 8. Which structures count as load-bearing is decided by the design organisation on the basis of the building’s structural design scheme, and it incorporates the fire protection measures into the design.

That is why any conversation about price starts with two questions: to what rating are we protecting, and which elements exactly. The schedule of elements with R ratings from the design is the basis of both the calculation and the cost estimate.

Terminal: structures in full view of passengers

Fire safety codes place stations and airports in a separate functional fire hazard class — F3.3: many people, large halls, long evacuation routes. In a passenger terminal, columns, trusses and bracing are often not hidden behind a suspended ceiling — they become part of the architecture. Hence requirements that a warehouse does not have.

Appearance. Thin-film intumescent paint is applied in an even coat without runs and covered with a finish enamel matching the interior colour. Compatibility of the finish enamel with the fire-protective compound must be confirmed by the manufacturer — a random “nice-looking” enamel can prevent the coating from intumescing in a fire.

Connections and thin elements. Tubular trusses, gusset plates, bolted joints — they have their own reduced metal thickness, usually smaller than that of a column, so for the same rating they need a thicker coat. Under ShNK, the fire resistance of a structure’s connection must be no lower than the required fire resistance of the structure itself, so gusset plates and joints go into the calculation as separate lines, not “by tonnage”. How the thickness is calculated for each section is covered in the article on calculating fire-protective coating thickness.

Access for renewal. ShNK requires the technical documentation for a fire-protective coating to state the interval for its replacement or renewal, and does not allow such coatings where they cannot be periodically renewed. For a terminal with structures under a high roof, this is a design question: how will they be reached in ten years — from a lift, from scaffolding, from service walkways.

Hangars and technical buildings

A hangar means a large span, doors across the entire end wall and often no heating. In winter, condensation forms on cold steel, and with the doors open the structures near the entrance are practically outdoors. So before buying material, three questions need to be settled: whether the product is suitable for an unheated space, whether a protective topcoat is needed, and at what temperature work can be done. Water-based fire-protective paints are applied at a temperature of at least +5 °C — in winter this means working inside an insulated enclosure or rescheduling.

For the terminal and heated spaces, the white thin-film TERM-007 is suitable: it raises the fire resistance of steel structures up to 120 minutes, is certified in the Republic of Uzbekistan in accordance with the law and has all permits for use. In dry rooms it needs no topcoat; in humid rooms it is covered with a protective enamel. Where a structure is exposed to the weather, a weather-resistant product is needed — for example, the grey TERM-009.

Aviation fuel depot: a different fire scenario

At a fuel and lubricants depot and at a refuelling facility, it is not the building that burns but spilled fuel, and the temperature rises much faster than in an ordinary indoor fire. Fire protection for buildings is tested against the standard fire curve; for structures in an area of possible hydrocarbon spillage, the design may require a material tested against the hydrocarbon fire curve. This question is worth putting to the designer before purchase, not at acceptance.

A separate topic is the internal linings of aviation fuel tanks. They are in contact with the fuel, and in practice a specific brand is approved on the basis of a conclusion issued by GosNII GA (State Research Institute of Civil Aviation) on the results of tests — that the coating does not change the properties of the fuel. The binder type stated in the TDS does not replace such a conclusion.

Cables and penetrations

A terminal is packed with cable: baggage systems, security screening, communications, lighting, display boards. Under ShNK, places where cables and pipes pass through walls and floors with a rated fire resistance must not reduce their fire performance. For penetrations the rating is designated EI, not R, and it is confirmed by a specific sealing system. These are separate works: fire protection of cable lines and fire sealing of penetrations.

What to prepare before work starts

A schedule of elements with the required R ratings from the design — for columns, bracing, beams, trusses, purlins and connections.
The section size of each element: the reduced metal thickness is calculated from the cross-section dimensions, and the coating thickness from that.
Service conditions: heated space or not, humidity, exposed areas — these determine the product and the topcoat.
Primer: which anti-corrosion primer is already on the steel and whether it is compatible with the fire-protective compound.
The finish colour for visible structures and confirmation of enamel compatibility.
Acceptance procedure: thickness measurement coat by coat, a certificate of concealed works for surface preparation, a works log.

With such a schedule, the area and quantity of material are calculated for each item rather than from an average figure per tonne. If the fire protection design has not been done yet, it can be ordered separately.

Building or reconstructing an airport? Send us the schedule of elements or KM (steel structure) drawings — we will calculate the area and quantity of material for your rating. We ship TERM materials from the warehouse in Tashkent throughout Uzbekistan, including to Urgench and the Khorezm region. Write to us on Telegram or WhatsApp — we reply within a minute. Phone +998 90 918 81 88, email info@staterm.uz.

Fire protection of airport steel structures: terminal, hangar and which R rating the design requires