Specification of Metal Ceilings for Transportation Projects (Railway Stations & Airports)

Introduction

Transport infrastructure is crucial to our urban existence. With its growing population, Australia’s transport infrastructure needs across road, rail, ports and airports are increasing. In the post-COVID recovery, the focus in Australia will be on an infrastructure-led recovery with $14 billion in new infrastructure projects budgeted for 2020-21 alone.

Designers, architects and specifiers play a critical role in infrastructure projects that need to manage risk and safety, and ensure both community and commercial viability. Airports and railway stations are architecturally complex structures, placing high demands on functionality, aesthetics and performance. The ceiling, because of its size, is one of the critical elements in delivering a functional environment that people are comfortable in.

As a ceiling material, metal offers design flexibility as well as aesthetic and performance benefits. Taking a variety of forms – from planks and panels to curved beams and perforated options – metal can transform a space into a striking piece of modern architecture. Metal ceilings also fulfil vital functions, providing light, managing interior acoustics, and concealing and interfacing with electrical and mechanical services.

However, care must be taken when designing and specifying a metal ceiling to ensure a quality, long-lasting solution is delivered. This whitepaper addresses the issue of selecting the metal ceiling system most suitable for that purpose.

“Taking a variety of forms – from planks and panels to curved beams and perforated options – metal can transform a space into a striking piece of modern architecture.”

Why Metal Ceilings?

Key Benefits

Metal ceilings are used in a wide range of sectors, including offices, retail, health, education and transport infrastructure. Metal ceilings offer a range of architectural advantages:

• Design. Metal offers a modern, clean aesthetic with a range of colour options, finishes and profiles. Ceilings are available in linear or modular layouts, with metal’s dimensional flexibility enabling curved or sculpted forms to be achieved.

• Acoustics. Metal ceilings can be specified with a variety of perforations and infills to meet sound absorption and sound attenuation requirements.

• Durability. When specified correctly, metal ceilings are able to withstand rigorous handling, impact, and harsh environmental conditions.

• Humidity resistance. They are also able to withstand humidity fluctuations with no risk of warping or sagging.

• Hygiene. Metal offers a smooth surface that can be easily cleaned.

• Fire resistance. Metal is generally fire resistant and able to limit spread of flame.

• Integrated services. Lighting, electrical equipment, HVAC (heating, ventilation and air conditioning) systems, smoke detectors, cabling, sprinklers and other services can be installed within metal ceiling modules.

• Demountability. Metal ceilings lend themselves to easy service access. Ceiling tiles can be removed for service maintenance or cleaning, with minimal risk of tile damage.

Design Objectives for Infrastructure Projects

Transport infrastructure projects, such as airports and railway stations, are complex buildings with demanding requirements for functionality, longevity and durability. They operate around the clock and are expected to last for decades while subject to heavy foot and equipment traffic. Given their long service life, infrastructure buildings are likely to undergo multiple renovations throughout their existence yet are expected to operate with minimal disruptions.

Metal ceilings for transport buildings contribute to light reflectance and building acoustics, and can act as a visual barrier. They are also often designed to conceal and interface with electrical and mechanical services, meaning they will often contain piping, cabling and duct work. Suspended ceilings, referring to a secondary ceiling structure that creates a void between the underside of the floor slab or roof above and the top of the suspended ceiling, are the preferred method for concealing such services.

Another key consideration given the projected life expectancy of the building is maintenance access. Ceiling voids (also referred to as the plenum) contain not only electrical and mechanical services but also critical communication equipment and hardware, so the need for easy access to service and upgrade items contained in the ceiling must be addressed as high priority.

Ceiling designers should anticipate that the space will undergo several reconfigurations over its lifetime, and consider systems that can be easily disassembled and rearranged or adapted. Metal ceiling tiles, unlike plasterboard and mineral fibre tiles, are better suited for this purpose as they can be taken down and moved around with no ensuing damage.

Design Considerations for Metal Ceilings

Functional and Performance Requirements

A well-designed metal ceiling system will meet the functionality and performance requirements of the site as well as those imposed by law. Such requirements will cover acoustics, wind loads, humidity, fire resistance, earthquakes and sustainability as well as accessibility, security and safety. The specific requirements for each project will depend on the climate, geology and site conditions, the functional needs of the building, and the applicable building codes, standards and local regulations. Early scoping and consultation is required to ensure all relevant needs are identified as early as possible during the design phase.

As with any building project, functionality and performance must be balanced with other practical considerations. This includes the desired aesthetic of the space, budget and cost constraints, project schedules and labour requirements. Fast, flexible and cost-effective solutions that do not compromise on quality are generally preferred, making modular metal ceilings more attractive as they are easier to install relative to many other equivalent systems.

Ceiling Systems and Configuration

Transport infrastructure projects typically feature a range of ceiling applications depending on location within the building. Departure halls, platforms, concourse areas and high traffic areas tend to lean toward bespoke designs while back of house areas generally feature standard modular systems. A modular metal ceiling is comprised of a series of modules, tiles, grids and partitions that are arranged to optimise space as needed.

Common metal ceiling design systems include:

• Grid systems. A grid system features lightweight metal profiles, which are used to create the ceiling, arranged in a grid formation.

• Linear systems. Long ceiling panels to deliver continuity across the ceiling are the primary characteristic of linear systems. Linear systems focus on the length of ceiling panels, rather than their width, and are commonly specified for linear building applications such as terminals and corridors.1

• Open plenum. An open plenum system refers to when the occupied space is not separated from the space above by a continuous ceiling.2

• Curves. Some metal ceiling systems are specifically designed for curves with concave and convex metal panels.3

• Clouds. A cloud-like ceiling design features ceiling suspension and panels assembled into free-floating islands, pods and other similar layouts.4

Standardised Modular Systems vs. Bespoke/Custom

Modular ceiling systems in standard sizes dominate the ceiling industry driven by the need to fit together with modular fixtures such as lighting and air conditioning outlets. While these systems are suitable for the majority of buildings such as offices, hospitals and schools, they fail to cater for custom-designed ceilings such as those with curves, geometrically challenging shapes or nonmodular layouts.

Given the range of ceiling applications in a transport building, more likely than not a custom-designed ceiling will be required to meet all functional and aesthetic requirements, which presents some challenges. As there are only a relatively small number of metal ceiling specialists in the market, designers are often unable to locate workable details to incorporate into their design for these areas. As a result, they often leave the fixing details vague or create a system which demonstrates generally their fixing requirements but do not specifically address critical details like alignment and access. In other instances, design details are overengineered, unnecessarily increasing the cost of the ceiling system while at times still not addressing all of the functional requirements.

Material Composition

In general, metal ceilings utilise aluminium or steel. Steel is reliable for heavy duty applications as it provides ample strength and durability. In comparison, aluminium offers corrosion resistance, which is useful for exterior applications and is also lighter in weight, and thus easier to work with for architectural purposes.

Ceiling panels can be made from a range of materials. Soft panel ceilings are made from gypsum, mineral fibre, fiberglass and stone wool. Hard ceiling panels are typically made from wood or metal. For transport infrastructure applications, metal offers the requisite durability and strength. Metal panels also come in a variety of formats with some offering additional benefits. For example, expanded metal panels, which are metal sheets fabricated with a pattern of diamond or hexagonal-shaped openings, can reduce weight and cost, and provide ventilation.

Aesthetics

Designers can choose to hide a visible ceiling grid with a concealed suspension system or opt for an exposed ceiling for visual impact. Linear systems emphasise long, continuous lines throughout the building, which can complement a modern aesthetic.

Ceiling and panel designs can be specified solid or with perforations. Perforations can be as simple as holes spaced evenly apart, or complex with lineal, diagonal or staggered patterns. Custom patterns can be ordered and are sometimes used to convey logos or other graphical requirements, but such requirements add to cost and time for manufacturing.

The look of a metal ceiling can also be altered with different finishing techniques, including exposed metal face or solid colours, or painted, metallic and specialty finishes.

Installation

Metal ceiling installation should follow the relevant best practices, standards and guidelines. Designers should be aware of the key standards relevant to metal ceilings, which includes the following:

• AS/NZS 2785:2000 Suspended ceilings – Design and installation.

• AS 1170.4:2007 Structural design actions, Part 4: Earthquake actions in Australia (earthquake and seismic design/compliance); and

• ASTM C636/C636M – 19 Standard Practice for Installation of Metal Ceiling Suspension Systems for Acoustical Tile and Lay-In Panels.

Metal ceiling are generally cost effective and easier to install than other options, however several factors can add cost.

For example, applications that call for specialty finishes, or larger than standard sizes, can be more expensive than standard solutions. Engaging a metal ceiling specialist early in the design process is critical to balancing design, cost and timelines.

Access and Maintenance

Incorporating design accessibility that can be easily understood and operated by maintenance crews who were not involved with the initial installation is important. Different types of panels allow access to the ceiling plenum. Some systems feature removable clip-in panels or hook-on panels that enable maintenance crews to remove and reinstall the panel quickly and easily. Torsion spring panels, which enable the ceiling panel to be swung open, allow maintenance staff access without removing the panel.

Designers should strongly consider systems that provide maximum flexibility. A ceiling system that allows access at any point is generally preferred to one that only provides a single access location. While it has been traditional practice to have dedicated access panels, leading metal ceiling specialists offer ceiling systems in which every panel is demountable.

Designers should not overlook the ease of removing and replacing access panels. Progressive accessible systems, in which panels and components must be removed in sequence until the desired point of access is reached, can prove cumbersome. The weight of the panel is also a consideration. Heavy access panels, especially those requiring more than one worker to handle at an elevated height, are less safe than panel systems that are supported by the ceiling frame.

Balancing Access, Function and Design

Durlum Metal Ceilings

Durlum is a world class manufacturer of innovative ceiling systems characterised by products that can be customed to suit any requirement. Available in both standardised classic metal ceilings and individual (bespoke) designs, Durlum offers a wide range of project solutions. Optional features that can be incorporated into the design include specialty surface finishes, lighting, acoustics, perforations, advanced cooling systems and more.

With extensive experience in airport and rail station projects, Durlum approaches ceiling design differently and offer a program of engineering systems which can be adapted to accommodate custom-designed metal ceilings. An advantage of this approach is that engineering details are standard rather than the panels, so the systems can be used on non-standard panels such as curved, trapezoidal, and 3D shapes through small modifications to individual components. This flexibility allows a designer the comfort of applying tried-and-tested design solutions to challenging forms. It is also possible to adapt the systems to open ceiling systems like baffles or panels constructed of different membrane materials like expanded metal.

The company’s range of ceiling systems also include innovative access solutions that help improve the performance and longevity of the system. Such solutions include the philosophy of making almost every panel demountable rather than the traditional practice of having dedicated access panels, allowing much more flexibility for repair and maintenance teams assigned with searching for faults or addressing leaks above the ceiling.

Several systems also incorporate panel retention mechanisms, such as hinging or drop-and-slide systems, whereby the desired panels are lowered and moved horizontally underneath the adjacent panel. Often the panels in feature areas are large sized and heavy requiring up to four people to handle them on elevated platforms. The panel retention systems make handling large panels safer due to the panel’s weight being partially supported by the subframe system and requiring less workers. This reduces the chance of damaging the panel, but also increases safety and efficiency, and allows the worker to easily reposition the panel in its original place.

Exclusive to Network Architectural, the Durlum range of ceiling systems includes open-cell ceilings, expanded metal ceilings, chilled and heated ceilings, raft ceilings, illuminated-surface ceilings, luminaires, and lighting and daylighting systems.

For more information, visit the Network Architectural website

at https://www.networkarchitectural.com.au or email

[email protected]

“As there are only a relatively small number of metal ceiling specialists in the market, designers are often unable to locate workable details to incorporate into their design for these areas”