Fire protection in data centers Detection, alarming, evacuation, extinguishing ZZZ VLHPHQV FRP GDWDFHQWHU
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Content 1. Introduction .................................................................................................................................................... 5 1.1. Fire hazards in data centers ........................................................................................................................ 5 1.1.1. Fire load ................................................................................................................................................. 5 1.1.2.
3.4. Evacuation................................................................................................................................................ 21 3.4.1. Objectives ............................................................................................................................................ 21 3.4.2. Evacuation concepts ............................................................................................................................ 22 3.4.3. Organization .....
1. Introduction Safe data centers are the indispensable backbone of today’s highly engineered society. They are processing an ever-increasing quantity of videos, voice and data throughout a global network of several billion devices. Applications such as social media, cloud computing, online banking and e-healthcare solutions impact our life every day. In today's world, no one can afford not to be connected.
It must also be considered that modernization, reconstruction or remodeling of the data center can alter the fire load. If not already required by local codes and regulations, the chief engineer of the data center or a similarly qualified person should be permanently on the look-out for changes in the fire load, and should initiate appropriate measures to reduce fire risks as much as possible. 1.1.2. Fire risks Fire risks result basically from the probability of occurrence and the effect caused by fire.
1.2.1. Fire protection objectives The primary goal is to minimize any operational interruptions ‒ even in case of a fire ‒ and to protect people and property effectively. Fire safety is therefore a long-term investment that must be carefully planned to ensure the business continuity of a data center. If a damaging fire can no longer be prevented, the effects of the fire must be limited as efficiently as possible. Typical protection objectives are: • • • • • No business interruptions.
1.2.3.1. Passive measures Although passive protection measures are not the subject of this document, they are extremely important. The majority of passive protection measures are related to the building structure, construction methods, and materials used to make a building as fire resistant as local circumstances demand. The main elements of passive (structural) fire protection measures include: • • • • • • Fire compartmentalization of a building. Use of materials to prevent building collapse.
• • • • • • • • Detection measures Exterior lighting (area, entrance, emergency exits) Monitoring of the emergency exits Automated gas extinguishing systems Sprinkler systems Mitigation of acoustic trauma for human being and reduction of sound pressure levels on hard disk drives (HDDs) Manual fire extinguisher, wall hydrants Exterior hydrants (pillar hydrants, ground hydrants) Others The main tasks of an automated fire protection system are to detect (an incipient stage) fire, sound an acoustic alarm, not
Intervention measures To limit the danger to human life and the extent of the damage, it is extremely important to start intervention and extinguishing measures as soon as possible after the outbreak of fire. All extinguishing equipment must always be kept in perfect working order: this is a prerequisite for any successful intervention. Intervention measures activated by the fire control panel include: • Automatic closing of fire doors, dampers etc.
The below image shows typical rooms for fire protection in a large data center: 1 2 3 4 5 Large server room Electrical switching room Control room Room with security and safety equipment (e.g. extinguishing cylinders, etc.) Emergency power supply (e.g. generator and battery/UPS rooms) The following section briefly describes different typical rooms with regards to fire protection. More detailed information can be found for some of those rooms in separate documents (see below). 1.3.1.
1.3.2. Emergency power supply For data centers emergency power supply (e.g. generators or battery/UPS rooms) is mission critical as it ensures business continuity in case of blackouts. Therefore, specific attention has to be taken to protect these areas. With the help of fast detection, operators are quickly informed about an event and all required technical and organizational measures can be started immediately.
1.3.4. Control rooms The control room needs to be a safe environment for operating and supervising the data center. All disciplines critical to the data center can be monitored by a management station. The management of all kinds of events must be ensured at all times. Personnel and equipment must be protected and allowed to perform even under difficult circumstances. An early and reliable fire detection system and a clever alarming concept is the right choice.
1.4. Purpose of this document This short introduction shows how complex the problems of fire protection in data centers are, especially if one considers the great variety of buildings which exist. It becomes clear that each building has to be considered on an individual basis. As a result, the establishment of universal guidelines is quite complicated. This document provides an overview of the most important topics in technical fire protection for data center applications.
2. Fire detection The earlier a fire is detected, the more time there is for evacuation and extinguishing, and the less damage can occur. Earliest possible detection is thus the key to minimizing damage and gaining precious intervention time. 2.1. Fire basics To ensure reliable, early detection of fire, it is important to be familiar with the different fire phenomena, fire propagation and possible deceptive phenomena. 2.1.1.
In general, the higher the room, the greater the distance between the seat of fire and the fire detectors on the ceiling. This is why the intensity of the fire phenomenon to be detected (e.g. smoke density, temperature increase or radiation intensity) decreases with increasing ceiling height.
2.2.2. Elements Extinguishing system Figure 2.2.2-1 Setup of a fire detection system Periphery Fire-related information is collected from all parts of the building by the input periphery (automatic detectors, manual call points and input contacts) and transmitted to the control unit. The intelligent, automatic fire detectors (point-type detector or aspirating smoke detection) detect and analyze the different fire phenomena and automatically report the current hazard levels to the control unit.
3. Alarming and evacuation 3.1. Introduction Once a fire has been detected by an automatic detector or by a person activating a manual call point, the fire detection system will generate the preprogrammed control and alarm signals. A major factor that can affect the success of building evacuation is that many people do not take the sounding of fire alarm sufficiently seriously or do not understand the meaning of the acoustic signal.
3.2.3. Alerting people in the building In case of an alarm in data center, a step-by-step procedure should be accomplished to investigate first. After verification of the situation if the situation cannot be contained or creates risks beyond the capabilities of the personnel in attendance then a general alarm (evacuation) can then be activated Acoustic alarms Acoustic alarm equipment is used to alert people in the danger zone as well as internal intervention forces.
3.2.6. Alarm Verification Concept AVC Figure 3.2.6-1 Alarm Verification Concept The Alarm Verification Concept (AVC) allows in-house personnel to carry out a local investigation before the municipal fire service is alerted or the building evacuated. This reduces the number of unnecessary calls and is based on a dual timing principle. It is only applicable to the “day/manned” mode of the fire detection system.
3.3. Smoke control 3.3.1. Objectives Smoke presents the greatest danger to life in the case of a fire. This is not only due to smoke inhalation injuries and asphyxiation, but also due to smoke-filled corridors and staircases, which make evacuation considerably more difficult and raise panic levels. For this reason it is imperative that smoke is restricted to the immediate locality of the fire for as long as possible and is actively extracted from the building by appropriate means.
3.4.2. Evacuation concepts For each data center an appropriate evacuation strategy must be defined in accordance with the physical organization of the building, local regulations and in discussions with the local fire authorities. Visual, sirens and alarm horns As soon as a visual, siren or horn is activated personnel inside the building must evacuate, including personnel in the data room (center).
4. Extinguishing 4.1. Introduction When it comes to data centers, NFPA (National Fire Protection Association) provides most details on how to protect it against fire. NFPA 75 for example says that if a building has a water sprinkler standard, then usually so should the data center, too. But it needs to be kept in mind that water-based fire protection systems, such as sprinklers, provide primarily structural protection and not asset protection.
4.3. Extinguishing agents A variety of extinguishing agents are used, each of which utilizes one (or more) of the above mentioned mechanisms. 4.3.1. Gas Gases are fast, highly efficient, electrically non-conductive and clean. Their properties make them particularly suitable for rooms with high value content.
4.3.3. Chemical powder Extinguishing powder relies on interrupting the combustion process by interfering with the chemical reaction and the associated extraction of energy. Powder is mainly used in fire extinguishers. One disadvantage of this type of extinguisher is that it leaves a very fine residue which is difficult to remove and is highly corrosive. The powder is also incompatible with electrical and electronic equipment. 4.3.4. Water The most commonly used extinguishing agent is water.
Extinguishing is controlled either manually or preferably automatically by means of a fire detection system. Only a quick, faultless actuation prevents consequential damage, as a fire should be extinguished during its formation phase. However, to prevent human casualties, an alarm must first be sounded to warn people of the imminent flooding of the area. The gas will only be released after a predefined delay has given people sufficient time to evacuate the area.
4.4.2. Fire extinguishers Fire extinguishers are mobile or portable manual devices designed for preventing incipient stage fires from getting out of control. The extinguishing agent is expelled under pressure. In some types of extinguisher the agent is kept under constant pressure, while in others the pressure is generated by releasing a propellant gas at the time that the extinguisher is activated. Extinguishing agents include water, foam, carbon dioxide and powder.
4.4.3. Wall hydrants Wall hydrants are used to complement fire extinguishers in dealing with incipient stage fires. They are intended both for trained staff and fire service use. Wall hydrants are evenly distributed throughout the building, providing water outlets from the building’s extinguishing water pipe network. Care must be taken to prevent contamination of the drinking water supply by the water used for extinguishing.
4.5. Extinguishing in data centers A data center is a complex building with diverse demands on the extinguishing infrastructure to be provided. What is installed will be largely determined by: • • • • Local building codes Insurance guidelines Official fire protection reports Size of the property 4.5.1.
Sound impact on hard drives and storage systems Siemens has investigated the influence of noise on hard disk drives and storage systems intensively. The findings conclude that all today available magnetic hard disk drives are noise sensitive. Therefore, the performance of hard disk drives can be disturbed by the high noise levels during the discharge of dry extinguishing systems.
Figure 4.4.2-1 Modular and centralized extinguishing systems Pressure relief in installation of gas extinguishing systems Overpressure flaps are a must when a gas extinguishing system is installed! Protection of the building Overpressure flaps prevent the damage from the dangerous overpressure caused when discharging a gas extinguishing system.
Protection of room In a data center configuration with cold / hot aisles (see fig. 4.4.2-2 and 4.4.2-3), the extinguishing flooding process presents some differences compared to traditional room flooding. • The flooding of the racks with circulation system active (considered to be the expected situation) will mostly occur through the nozzles located in the false floor.
The extinguishing agent concentration in the area to be protected is one of the key parameters (design concentration). The entire gas extinguishing system design must aim at establishing the desired concentration within the so-called flooding time, in the room to be protected. Of course, it is vital that the room to be protected is capable of allowing the establishment of the extinguishing agent concentration and maintaining it during the retention time.
Room preparation When a room is being prepared to host an extinguishing system, some key integrity aspects have to be taken into account: • All windows have to be fixed closed or automated to be operated by the extinguishing control system, before the extinguishing agent is released. • Doors have to be automated (magnet device or similar) to automatically closed by the extinguishing control system, before the extinguishing agent is released.
Installation Location of the extinguishing cylinders The cylinders shall be placed if possible outside the protected area in a separate room or corridor close as possible to the risk area to reduce pipe lengths. If the cylinders are stored in a corridor, safety precaution shall be taken to avoid unauthorized actuation of the extinguishing system. Installation of piping network Pipes and pipe connections shall be made of metal and be able to withstand the maximal possible pressure.
4.6. Advantage Engineering – share the experience With our dedicated program for consulting engineers, you can benefit from our extensive application know-how and complete portfolio. With Siemens, you can offer your customers comprehensive fire safety for any application and environmental condition. Your customers will appreciate this as it enables them to reliably protect people, assets and business processes from fire.
Siemens Switzerland Ltd Building Technologies Division International Headquarters Gubelstrasse 22 6301 Zug Switzerland Tel +41 41 724 24 24 The information in this document contains general descriptions of technical options available, which do not always have to be present in individual cases. The required features should therefore be specified in each individual case at the time of closing the contract. The document contains a general product overview. Availability can vary by country.
