ASD article for Network Communications News
Next generation advanced aspiration smoke detection supportsdata centre uptime.
Tim Checketts
Honeywell
Outages, the constant threat
Tasked with providing a 24/7/365 service, data centre managers are well aware of the operational issues that can cause equipment outages and downtime:power outages, cooling system failures, and individual server issues are all high on the agenda.They are normally dealt with through N+1 redundancy of critical equipment - with good reason.Data centres reserve spare or redundant servers and provide uninterruptible power supplies to manage the risk of hardware failures and power outages in order to deliver target uptime of 99.9999 percent.
In a recent study of US data centres by the Ponemon Institute, sponsored by Emerson Network Power,the cost of downtime has increased significantly in the last three years. Each unplanned outage now costs an average of US$7,900 per minute. The average reported incident length was 86 minutes, resulting in average cost per incident of about $690,200. For a total data centre outage, which had an average recovery time of 119 minutes, average costs were about $901,500. The report analysed costs of damage to mission-critical data, impact of downtime on organizational productivity, damage to equipment, legal and regulatory repercussions and lost confidence and trust among key stakeholders.
The ever-present danger of fire
Fire is another well-recognised potential hazard, with automatic detection systems routinely installed throughout the facility. Providing effective fire protection for a data centre poses some interesting challenges. In a typical year, two-thirds of all fires in commercial buildings start in power and climate control equipment, both critical elements of any data centre. In a large data centre which may house several thousand racks, up to 40kW of heat can be generated in each 800 x 1200 x 2000mm server rack, so an overheat condition can develop extremely rapidly if there is failure in the heat removal equipment. If the data centre is fitted with an automatic extinguishing system, the clean-up requirements can be as disruptive to the business as the fire it has quenched.
The majority of these costs are incurred because the events are unexpected or occur with very little notice, giving the data centre management team limited time to respond in an orderly fashion.If the outage is caused by a fire, then speed of detection is critical in preventing a major catastrophe.
The data centre is a hostile environment for fire detection
The effects of a fire can range from insignificant to catastrophic depending on the size, speed of development and location of the blaze.
The data centre environment is not friendly for fire detection systems. With large amounts of electricity being distributed around the facility, overheating cabling is a very real issue. Cabling typically runs either under the false floor or above the server racks, both difficult areas to protect for an automatic detection system. Computer room air conditioners, CRAC, create very high airflows and the filters used by the CRAC units can remove smoke particles, again making smoke detection extremely challenging. Smoke dilution due to high airflow movement is a further issue, as are the large temperature variations between the air in the hot and cold aisles, another potential source of point smoke detector false alarms.
The solution: ultra-sensitive very early warning detection from an aspiration detection system (ASD)
The most effective fire detection technology for data centre protection is a high sensitivity aspiration system, in which a network of sampling pipes draw air from the protected area and delivers it to a remote high sensitivity detector. It is a critical requirement that the detection system gives very early warning of a fire to allow enough time for the impacted equipment to be taken offline and data to be moved to another part of the network before wider damage or loss of data is caused.
The ultra-high sensitivity of an aspiration system is the only practical technology to give the warning time required in such operations; however, the technology used to deliver this very early warning in the past has been prone to false alarms. To the data centre manager, a false alarm has the same impact as a real fire.Typically, one of the first responses to a fire alarm is that the affected server racks will be powered down, so for the operator, a false alarm is as problematic as a real outbreak.
Significant advancementshave been made in the technology of the latest ASDs to come to market. They are able to respond to the products of combustion from an overheating cable hours before smoke becomes visible.
The latest ASDs include sophisticated filtration to deliver ultra-high sensitivity (as much as 0.0015% obs/m) without the danger of false alarms – preventing unnecessary shutdown.Systems also now have TCP/IP connectivity, enabling remote interrogation and monitoring. Alerts can be automatically broadcasted by email, a benefit to data centre managers. Modbus protocols are also embedded, enabling seamless integration with DCIM systems without any additional hardware or software and delivering comprehensive communications with the fire control panel
Applicable standards
ASDs, as part of a fire detection system, have to be approved to EN54-20, a mandated product standard under the Construction Products Directive (CPD). The standardsets out a classification system for aspiration systems, definingClass A, B and C sensitivities.Unsurprisingly, data centres are firmly in the highest, Class A category.
EN54-20 Class A: Very High Sensitivity for Strategic Operations
A minimum sensitivity of 0.05%dB/mis defined, applicable where very early warning is required in enterprise-critical applications such as telecoms facilities, computer rooms, data centres and financial institutions. Designed primarily for areas where high levels of air conditioning and air dilution exist.
Key concerns are:
• Potential revenue loss due to down time
• Avoiding smoke, fire and water damage
• False alarms
• Prevention of false discharge of extinguishing systems
• Effective detection in very high air velocity environments
CPD approved seminar programme
For those who wish to gain a greater understanding of the issues and benefits of aspiration detection, aspiration detection providers such as Honeywell offer free of charge, CPD approved seminars on the latest aspiration technologies. These are aimed at consultants, specifiers and installers working in the fire system design, architectural, mechanical and electrical contracting and facilities management sectors. Go to find out more.
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Notes to Michael Crane 05 March 2014.
Contact details for publication:
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System Sensor Europe
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About System Sensor
System Sensor Europe is owned by Honeywell and is the world's largest manufacturer of fire detectors for use in conventional and addressable fire detection systems.
About Honeywell
Honeywell International ( is a Fortune 100 diversified technology and manufacturing leader, serving customers worldwide with aerospace products and services; control technologies for buildings, homes and industry; automotive products; turbochargers; and specialty materials. Based in Morris Township, N.J., Honeywell’s shares are traded on the New York, London, and Chicago Stock Exchanges. For more news and information on Honeywell, please visit