The fire triangle is a simple model that illustrates the three elements that a fire needs to ignite and sustain:
oxygen, heat, and fuel. Oxygen is the oxidizing agent that enables the combustion reaction, heat is the energy source that raises the temperature of the fuel to its ignition point, and fuel is the material that reacts with oxygen and releases heat and light. Removing any one of these elements can extinguish a fire. For example, water can reduce the heat and the oxygen, sand or soil can smother the fuel and the oxygen, and fire extinguishers can displace the oxygen or lower the temperature.
References: EPI Data Centre Professional (CDCP®) Reference Materials, page 66.EPI Data Centre Framework, Module 4: Fire Protection, page 4. 1, 2, 3.

The expected time to recover or repair from a system from a failure is defined as MTTR (mean time to recovery or mean time to repair). MTTR is the average time it takes to restore a system or product to its normal operation after a failure. MTTR includes the time spent on detecting, diagnosing, and fixing the problem. MTTR is an important metric for measuring the reliability and availability of a system or product, as well as the efficiency and effectiveness of the incident management process. A lower MTTR indicates a faster and more reliable recovery or repair process.
References:
*EPI Data Centre Professional (CDCP®) Preparation Guide, page 17
*What is MTTR? | IBM
*Explained: All Meanings of MTTR and Other Incident Metrics

Busbar trunking systems are a method of power distribution using rigid copper or aluminium conductors to distribute the power around a building. Busbar trunking systems have many advantages over cables, such as lower space requirements, higher short-circuit strength, lower fire load, and easier installation. One of the main advantages of busbar trunking is that it allows for flexibility in terms of power transmission and distribution.
Busbar trunking systems can be easily relocated, modified, or expanded to accommodate changes in the building layout or load demand. Busbar trunking systems can also be fitted with various components, such as tap-off units, elbows, tees, and end feed units, to provide power to different locations and consumers. Busbar trunking systems can also be installed both overhead and under the raised floor, depending on the design and preference of the building.
References: Why I prefer busbar trunking systems more than cables | EEP, Why should you choose Busbar over Cable? - E+I Eng, Busbar VS Cables for Riser Applications - An Electrical Engineer.

Sprinkler heads used in computer rooms activate at 57 °C (135 °F), which is the standard temperature rating for ordinary sprinklers. This is the temperature at which the heat-sensitive element of the sprinkler head, such as a glass bulb or a fusible link, breaks or melts, allowing water to flow from the sprinkler. Sprinkler heads are designed to activate only when exposed to a fire, not to ambient temperature fluctuations. Therefore, sprinkler heads should be installed at a sufficient distance from the heat sources, such as servers, racks, or ducts, to avoid accidental activation. Sprinkler heads should also be selected and installed in accordance with the relevant standards and codes, such as NFPA 13 and NFPA 75.
References:
1: CDCP Preparation Guide, page 24, section 2.4.3 2: Sprinkler Systems in Data Centers3, page 1, section 1 4:
Data Center Fire Protection5, page 1, section 2 6: Data Center Sprinkler System Design7, page 1, section 1

The fire triangle is a simple model that illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). A fire naturally occurs when the elementsare present and combined in the right mixture. A fire can be prevented or extinguished by removing any one of the elements in the fire triangle.
References: EPI Data Centre Professional (CDCP®) Preparation Guide, page 9; Fire triangle - Wikipedia; The Fire Triangle Explained - Fire Action