Definition

We design and build helipads for commercial and residential buildings, government installations and hospitals. The design of these helipads follows the relevant Civil Aviation Code of the country of installation. However, for countries which are signatory to the International Civil Aviation Organization (‘ICAO’), the ICAO codes are usually followed. Relevant Codes here include Annex 14 and the Heliport Manual (9261-AN903-1995) and appendices. These codes prescribe the helipad size, structural criteria, location, lighting, heli approaches and other data. The data below relates more to helipads built to ICAO and European standards, which are somewhat more stringent, than US standards.

SIZE

The size of an ICAO governed helipad is not a simple formula but if we were to condense it for ease of understanding:

Diameter = OL x 1.5 + safety area which is the greater of 2 x 3m or 2x 0.25OL. OL refers to the overall length or breath of the helicopter, whichever is greater. So, the helipad size for a Sikorsky S76 is 16 x 1.5 + 2 x 4m = 32m.

Perhaps recognizing that this formula led to excessively large helipad sizes ( which is not a real problem with ground level helipads but creates problems in elevated situations) with corresponding cost effects, the ICAO have amended this to remove the safety area (need not be ‘load bearing’ and therefore could theoretically be in space) and reduced the overall size of the helipad. The overall size of a Performance Group 1 helicopter helipad for helicopters above 3.2MT becomes smaller at 1.0D, contrasted with the current 1.5D plus safety area. This results in a huge reduction in helipad size. These amendments are expected to come into force when all signatory countries agree to them. At this time, our best estimate of this is Dec 2008.

Safety considerations

To understand the need for adequate rescue and fire fighting services at the helipad, it is helpful to look at a couple of different Code requirements. The UK CAA has assessed the level of risk from fire following an accident on elevated sites as being potentially catastrophic and all flights for which Rule 5 Permissions are necessary will attract a condition that the recommended levels of protection and response for operations to elevated sites are in accordance with ICAO Annex 14, Volume 2, Chapter 6 (Table 6-3) and the ICAO Heliport Manual Chapter 6. This condition will be applied to all flights.

UKCAA-

• 6.2 “Particular problems arise from the operation of helicopters at elevated heliports that require special attention with regard to the rescue and fire fighting provisions. One important aspect is the confined and restricted space available on the average elevated heliport. This will impose restrictions on foam monitor and/or hose positioning and general fire fighting tactics. It is feasible that an accident could result in a fuel spill with a fire situation which could quickly cut off or reduce the already limited routes of escape to a place of safety for the helicopter occupants. In addition the accident or fire may involve rescue and fire fighting facilities located adjacent to the landing area. As a result the requirement for the amount of extinguishing agent at elevated heliports is based on a fire fighting action which may be required to last much longer than at surface level heliports. In addition, at an elevated heliport, rescue and fire fighting svcs should be immediately available on or in the vicinity of the landing area whilst helicopter operations are being conducted in order to achieve a rapid ‘knock-down’ response.
• At an elevated heliport, at least one hose line, complete with nozzle/branch pipe and capable of delivering foam in a jet spray/aspirated pattern at 250 L/min, should be provided. It is also considered essential at an elevated heliport to be able to apply the fire fighting agents, both principal and complementary, to the entire landing area irrespective of the wind direction. To achieve this and to overcome the possibility of a monitor being involved in the accident, it is necessary that at elevated heliports in Category H2, that at least two monitors be provided each having a capability of achieving the required discharge rate, and positioned at different locations around the helideck so as to ensure the application of foam to any part of the landing area under any weather conditions. Alternatively, a system of hand controlled branch lines or a deck integrated fire fighting system (DIFFS) may be considered. Further technical guidance is available in CAP 437; ‘Offshore Helicopter Landing Areas - Guidance on Standards’, Chapter 5. To further ensure the application of the agent to the entire landing area, monitors should preferably be operable from a remote control position located clear of the landing area and easily accessible.” (Source: PROVISION OF RESCUE AND FIRE FIGHTING SERVICES (RFFS) FOR HELICOPTERS AT ONSHORE UNLICENSED OPERATING SITES USED FOR THE PURPOSE OF PUBLIC TRANSPORT OF PASSENGERS - UKCAA, 2005)

INTERNATIONAL CIVIL AVIATION ORG:

• Similarly specifies the levels of protection needed for elevated helipads by dividing them into H categories according to the size of the helipad. H1 helipads are upto 15m in dia, H2 upto 24m and H3 from 24 to 35m. As an example, an H2 helipad will require (a) performance level B foam applied at 500lpm for 10 minutes plus (b) complementary agents which are usually hand held fire extinguishers to be situated at the helipad area.
• ICAO also cautions that ‘although the amount of fuel carried by helicopters is generally less than that carried by aeroplanes, a more serious fire situation can occur as the fuel tank is located underneath the occupied portion of the fuselage and close to the engine. In other words, burning fuel in a helicopter crash is more likely to remain within the area adjacent to the helicopter and thus the resulting fire situation may be more serious than one involving an aeroplane of similar size.’ (Heliport Manual, 1995, para 6.1.7)
• The best way to meet these requirements and to afford the maximum fire protection for helicopter crew, passengers, building occupants and third parties adjacent to the building is to instal a DIFFS system to the helipad. The helipad itself should be of the Enhanced Safety™ type which contains a built-in, automatic fire suppression system.

Practical considerations

Consider the following when planning your elevated helipad

• Size of the helipad (discussed above) and connected with which type of helicopter you intend to operate
• Loading considerations- more critical for existing buildings than new builds, can the roof columns take the dynamic and static loads from the helicopter
• Structural considerations- how will the helipad be supported? A trussed support frame may be best as this can allow reaction loads to go directly into the building columns rather than the roof
• Turbulence and placement of helipad- this is a complex topic and cannot be discussed at length here. “Preferably, the helipad should be elevated such there is a clear space of at least 6ft (2m) in height between the pad and the supporting roof. This will prevent additional turbulent flow from being generated and allow more streamline flow over the helipad” (“Evaluating wind flow around buildings on heliport placement”- Federal Aviation Administration, USA, DOT/FAA/PM-84/25)
• Fire and safety issues – as discussed above
• Installation of the helipad- a lightweight, pre-fabricated unit is best when working in crowded areas. Installation time can be a fraction of that for an in-situ placement such as concrete.
• Maintenance – design for minimal maintenance. This is especially critical when the helipad is cantilevered out of the building top. Again, an aluminium helipad requires virtually no maintenance.

Royal Melbourne Hospital Astech helipad

A recessed ramp is a good idea which allows quick access to fire extinguishers without compromising height restrictions.

Helipad on 62nd floor of TM HQ building in Kuala Lumpur, Malaysia

Astech safety helipad being installed for Caverton’s riverside heliport in Nigeria and to be used for airport shuttle flights...

Mater Hospital helipad in Brisbane, Australia.

Another view of the Mater helipad. Note the free air space below the helipad which reduces landing turbulence.

Safety helipad on a hospital rooftop. This helipad is equipped with an automatic DIFFS unit which utilizes UV/IR sensors to trigger...

Dual helicopter (AB139) operation helipad for HK Macau ferry terminal, in progress. Other features include dual link bridges between helipads and...

Ease of installation: the pre-fabricated alu helipad can be quickly installed in sections which are designed in accordance with lift...

Helipad structure is trial fitted at factory before being dismantled and shipped to customers in knocked down form. Only bolting is...

A rooftop helipad in progress for a customer in India. Owners of rooftop helipads in crowded areas of a city can often make a...

Strong and lightweight: high strength aluminium alloys allow complex structural arrangements as can be seen in this...

Helipad for a customer in Mumbai, India. Fully installed in 4 weeks from delivery.