What are the key drivers for roof cover board specification in mission critical environments, and why?


The key drivers for roof cover board specification in mission critical buildings are centred around the overriding objective to minimise downtime of the facility, which must operate 24/7 without interruption. Specifiers look for the roof to provide superior protection from the elements and resistance to fire spread from an internal or external source.

Protection from the elements can only be achieved through a highly resilient and robust roof assembly that minimises the risk of product failure over time whilst ensuring the roof’s ability to withstand extreme weather instances. Wind uplift, resistance to repeat hail strikes and adverse weather events are just some of the typical specification drivers for all mission critical projects.

If the flat roof assembly can help to resist the spread of fire within the building, this can minimise damage, disruption, and downtime. The potential risk of an external fire, spread from nearby buildings, either directly or through embers carried by the wind, should be considered in relevant instances. There’s also the possibility that roof mounted building services, such as photovoltaics, fail and subject the roof assembly to localised attack from fire.

Each mission critical project has slightly different roof cover board specification objectives, driven by legal obligations and specification customs across geographical zones and countries. Insurance requirements are also becoming a significant specification factor. It is key in the US, where product specification is often driven by FM Approvals which set performance standards through independent testing. In Europe, FM Approvals is not yet pivotal but are increasingly considered by some designers and architects. FM Approvals are more likely to be significant in the specification process in the Middle East, Asia, and Europe.

Roof cover board specification drivers – Data centres

Data centres are designed to safely house equipment, tend to be cuboidal in shape and are not designed with the light and air requirements of buildings for human occupation. Most services are positioned outside the building, allowing maintenance to be undertaken without affecting the sensitive interior humidity and temperature levels and putting the invaluable technology at unnecessary risk.

Data centre technology is particularly vulnerable to moisture and vapour, and specifiers lean to building components that can reliably prevent moisture ingress and are robust enough to ensure a low risk of failure over long periods.

Downtime risk mitigation is one of the pivotal design objectives in data centres, so a robust roof that offers maximum protection and requires minimum maintenance is critical. A study into the cost of downtime in data centres by Emerson Network Power (2010) in the US included data from 41 independent, average sized facilities. The study found an average financial loss of £4,131 per minute or £247,000 per hour (the original study values are $5,600 and $336,000, respectively).

Data centre roofs are frequently used to house a considerable amount of HVAC (Heating, Ventilation and Cooling) plant and building services, and this poses multiple risks to the integrity of the elements of the roof build-up during its construction and once the building is finished. The extra weight of the plant and higher numbers of service penetrations on the roof increases the risk of damage to the waterproofing membrane. Increased foot traffic and dropped tools during installation and maintenance of the plant also drive the need for a robust roofing solution to be specified.

Further drivers for flat and low slope roof assembly specifications are the overall cost and the speed of assembly. The sooner the data centre is weatherproofed, the sooner it can operate and create revenue. Regardless of the roof type, installation methods, and roof build-up components, products such as roof cover boards that can help expedite the weatherproofing stage can be crucial to giving the data centre business edge in an incredibly competitive sector.

Roof cover board specification drivers – Airports

Airports today are far from the utilitarian facility of the past as air travel is now a familiar mode of transport. Modern airports are functional, aesthetically pleasing, and designed to offer travellers a comfortable and calm environment.

Unlike the roof design of a data centre, which seeks to be cost effective, the design of airport roofs seeks to attract attention and make a statement. Roof types, roof covering selection and roof build-up will vary. The common aim is the aesthetic impact of the finished building and the speed of construction. ‘Wild air’ requirement, otherwise known as early weatherproofing, is often a requirement that is commercially driven.

Acoustic comfort is crucial to the quality of customer experience within airports. The main design objective is sound attenuation, but some airport designs include measures to improve sound absorption. The acoustic performance of the roof should be considered early in the design stage.

Roof cover board specification drivers – Biotech facilities

The requirements for biotech facilities relate to those of data centres. The key driver for biotech roof design is the preservation of expensive and often difficult to replace equipment, protection of sample collections, and downtime reductions. Unlike datacentres, biotech facilities are also designed with humans in mind and include more elements to ensure adequate daylight provision, indoor air quality etc.

The design and the build of these facilities seek to maximise value, and as is the case with data centres, the roof assembly tends to be of lower weight to ensure cost efficiency. Flat and low pitch metal roof decks and high-performance roofing membranes are frequently specified for the biotech sector.

As with data centres, the roofs often house heavy plant and various equipment, so roof access is critical to maintaining the functional infrastructure around the clock. The roof assembly must be robust and withstand natural forces and any accidental damage by flying debris or human error.

Roof cover board specification drivers – Museums and heritage buildings

Newly built museums follow a similar path to airports as architecturally striking buildings offering visitors calm, pleasant spaces. Acoustic performance is crucial to the visitor experience, as is the building specification that can help to preserve and protect valuable museum exhibits successfully. Robust protection from external damage by weather or unexpected human interaction to increase the longevity of the museum roof is therefore paramount to the design of these buildings. Where a museum roof requires refurbishment, the weight of components may be limited by the loadbearing capabilities of the building and the potential cost of any reinforcement.

Designing and reconstructing roofs of heritage buildings to the same standards can be a complex task. These roofs tend to have intricate detailing, parapets and architectural components that can pose a risk of moisture ingress. Material compatibility is crucial to delivering a homogenous, robust roof surface that is in keeping with the building. The choice of materials used in the final roof assembly should be considered when specifying the structural requirement of the deck (particularly applies to roofs with profiled steel deck). Whether using lower compressive strength non-combustible insulation or products with a higher compressive strength, attention should always be paid to protecting them from compression by heavy footfall or the weight of the plant installed on the roof.

Which roof cover boards meet the specification for mission critical buildings?

Roof cover boards can help to enhance the robustness and resilience of the roofs of mission critical buildings due to their position between the waterproofing membrane and the insulation layer. They add an extra layer of robustness to the build-up that helps to ensure the high performance of the roof elements and increase the resilience of the waterproofing layer to damage that could lead to water ingress. Roof cover boards made from non-combustible materials can also help enhance the fire resistance of the roof.

Georgia-Pacific has a range of non-combustible, glass mat faced gypsum core boards suitable for use in mission critical buildings. If you would like to understand more about the requirements of mission critical facilities, you can download our white paper or contact one of our team today who will be happy to help.

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