5.The fuel load of the room or structure has a significant impact on the development of a fire. The fuel load includes not only the structure itself but also the furnishings and contents, and the wall, floor, and ceiling coverings that feed a fire and offer it paths and directions with optimum fuel conditions. In evaluating a fire’s progress through a room or structure, the investigator must establish what fuels were present and where they were located. The chemical nature of the fuels and their physical forms will affect their ignitability and their expected heat release rate. In the reconstruction of a fire, the fuel load is not just the total number of joules or Btu’s of heat that can be generated but the rate at which that heat is released.

5.房間或建筑的火災荷載對火災發(fā)展有重要影響?；馂暮奢d不僅來(lái)自建筑本體，還來(lái)自建筑內部的家具和物品，以及墻壁、地板和天花板上的覆蓋物等可燃物。并且，建筑本體的可燃物還將為火災蔓延提供途徑和方向。調查人員在分析室內火災的蔓延過(guò)程時(shí)，必須查清室內存放的可燃物以及可燃物的位置?？扇嘉锏幕瘜W(xué)性質(zhì)及其物理狀態(tài)能影響其可燃性能，以及可預計的熱釋放速率。在火場(chǎng)重建過(guò)程中，火災荷載不僅包括可燃物燃燒所釋放的總的焦耳或Btu值，還包括其熱釋放速率。

6.Variations on the upward spread of fire or smoke will occur when air currents deflect the flame, when horizontal surfaces block the vertical travel, or when radiation from established flames ignites nearby surfaces. If fuel is present in these new areas, it will ignite and spread the flames laterally.

6.空氣氣流使火焰發(fā)生的偏轉、遇水平面阻礙（煙氣）垂直向上傳播以及火焰的輻射熱引燃附近物質(zhì)表面，都可能造成火災或煙氣向上蔓延趨勢的變化。如果火勢蔓延到的新區域存在可燃物，隨后將引燃可燃物并造成火勢進(jìn)一步蔓延。

7.Upward, vertical spread is enhanced when the fire finds chimneylike configurations. Stairways, elevators, utility shafts, air ducts, and interiors of walls and hollow support columns offer openings for carrying flames generated elsewhere, and fires may burn more intensely because of the enhanced draft.

7.當火勢遇到類(lèi)似煙囪的結構時(shí)，垂直向上蔓延將會(huì )增強。樓梯、電梯、公共豎井、通風(fēng)管道、墻壁內部和空心支柱都能為火焰提供開(kāi)口。因為通風(fēng)效果得到了強化，火勢發(fā)展將更加猛烈。

8.Downward spread will occur whenever there is suitable fuel in the area. Fire will burn downward across a solid fuel but at a rate that is a tiny fraction of its upward spread rate. Combustible wall coverings, particularly paneling, encourage the travel of fire downward as well as outward. Burning portions of ceiling and roof coverings, draperies, and lighting fixtures can fall onto ignitable fuels below and start new fires called fall-down or drop-down fires that quickly join the main fire overhead. Radiation from rollover fires or very hot gas layers can ignite floor coverings, furniture, and walls even at some distance, creating new areas of fire. The resulting fire patterns can be complex to interpret, and, once again, the investigator must remember to take into account what fuel packages were present from the standpoint of their potential heat release rate contributions.

8.只要有適合的可燃物，火勢就會(huì )向下蔓延?；鹧鎸⒀刂?zhù)固體可燃物向下蔓延，但是速度要比向上蔓延慢得多?？扇嫉膲γ娓采w物，尤其板面裝飾，將會(huì )使火勢向下或向外蔓延。天花板和頂棚覆蓋物、窗簾和燈具的燃燒部分可能滴落至下方可燃物，造成新的火災燃燒區域，稱(chēng)為墜落或滴落（drop-down）火災。新的起火區域將快速地連接到上方主體燃燒區域。滾燃或高溫煙氣層產(chǎn)生的熱輻射也可以引燃一定距離內的地面覆蓋物、家具和墻壁，并產(chǎn)生新的火災燃燒區域。由此產(chǎn)生的火災痕跡可能很難解釋?zhuān)坏┯龅?，調查人員必須記住，要從其潛在熱釋放速率的出發(fā)，分析存在什么可燃物。

9.Suppression efforts can enhance fire spread. Positive-pressure ventilation (PPV) or an active hose stream attack on one face of a fire may force it back into other areas that may or may not have already been involved, and push fire down, even under obstructions such as doors or cabinets. The investigator must remember those unusual conditions and check with the firefighters present.

9.滅火行動(dòng)可能加速火災蔓延。正壓送風(fēng)排煙（PPV）或對火頭展開(kāi)的主動(dòng)射流進(jìn)攻，可能使火頭退回并發(fā)展至其他區域（可能是未過(guò)火區域），并且造成火勢向下的蔓延，甚至蔓延至門(mén)、柜等障礙物的下部。調查人員必須記錄下這些反常的情況，并向當時(shí)滅火的消防員進(jìn)行核實(shí)。

10.Fire tends to flow through a room or structure much like a liquid—upward in relatively straight paths and outward and around barriers.

10.火災非常類(lèi)似于流體，傾向于穿過(guò)房間或建筑進(jìn)行流動(dòng)，可以沿著(zhù)筆直的通道向上流動(dòng)，也可以繞過(guò)障礙物向外流動(dòng)。

11.Ventilation from open doors, windows, or vents, or forced by heating, ventilating, and air conditioning (HVAC) systems or PPV fans can affect fire growth and movement as much as fuel arrangement. All ventilation must be documented.

11.就像可燃物的分布會(huì )對火災發(fā)展蔓延造成影響一樣，敞開(kāi)的門(mén)、窗或通風(fēng)開(kāi)口的自然通風(fēng)，以及熱量、通風(fēng)、空調系統（HVAC）或正壓送風(fēng)排煙（PPV）的強制通風(fēng)，都可能對火災的發(fā)展和蔓延造成影響。應該對所有的通風(fēng)情況進(jìn)行記錄。

12.The hot gas layer in a room can reach its critical intensity (producing a heat flux of >20 kW/m2) if the fire is large enough to overcome the leaks of hot gases due to openings or due to radiant and conductive losses. As seen in the 1985 Bradford (UK) football stadium fire, even a compartment that is open on three sides can develop flashover conditions when the fire gets big enough.

12.如果室內火勢足夠大，熱煙氣產(chǎn)生量高于開(kāi)口溢出量，熱量高于熱輻射和熱對流損失量，熱煙氣層可以達到其臨界強度（產(chǎn)生的輻射熱流量＞20kW/m2）。正如1985年Bradford足球場(chǎng)火災（英國）所見(jiàn)，當火災變得足夠大時(shí)，甚至一個(gè)三面開(kāi)口的房間都會(huì )發(fā)生轟燃。

13.Fire intensity in a post-flashover room is often greatest around ventilation sources. Thus, damage occurs more quickly around door sills, windows, or other openings where fresh air can be drawn into the room and can even reach walls opposite the opening.

13.在發(fā)生轟燃的房間，通風(fēng)口附近火災強度往往最大。因此，在門(mén)框、窗戶(hù)或其他開(kāi)口處，新鮮空氣可以進(jìn)入房間、甚至能夠到達開(kāi)口對面墻壁，這些區域呈現的火災破壞往往是快速并且嚴重的破壞。

14.The total firedamage to an object is the result of both the intensity of heat applied to thatobject and the duration of the exposure (with the realization that intensity ofheat varies considerably during a fire and that all the exposure may not have occurredat the same time).

14.火災對物體的整體破壞，既是熱量強度作用于物體的結果，也是作用持續時(shí)間的結果(應認識到，在火災中熱作用強度將會(huì )發(fā)生較大變化，所有的熱作用時(shí)間可能也不會(huì )同時(shí)發(fā)生)。