通过限制HVACR产品中可能泄漏到受限空间的制冷剂加注量，控制形成可达到可燃性下限（LFL）的混合物的可能性，可以降低可燃性风险。不幸的是，在现实生活中，定义空间或房间体积并不是一项简单的工作。定义房间的高度可能非常简单，但定义房间的有效楼层面积以计算房间体积可能非常困难、耗时，而且根据大量因素（包括房间中的障碍物或受限空间）而变化。要考虑的因素有房间填充、相邻空间、泄漏高度和自然对流等等。本文将介绍一种计算房间面积的有效方法。计算流体动力学（CFD）分析支持本文方法的合理性。 将描述确定不通风和通风空间的房间面积的不同方法，并证明隔墙、吊顶或连接房间的管道系统上方的区域不应被视为连接相邻空间。自然通风和强制空气循环将被确定，以确定计算房间容积的最大楼面面积。大部分工作是为了模拟1.8米（5.9英尺）高的壁挂式装置的制冷剂泄漏。在0.6米（2英尺）处运行了几个额外的点，以验证该方法，但没有对这些场景进行详细分析。将根据应用考虑各种安全因素，以确定使用ASHRAE标准34 A2L级易燃制冷剂所允许的最大制冷剂加注量。 将总结大量ASHRAE 34分类制冷剂的最大制冷剂加注量，以便在不同LFL端点进行比较。引用:2017年年度会议，加利福尼亚州长滩，会议论文

Flammability risk can be lowered by controlling the potential for forming a mixture that can reach the lower flammability limit (LFL) by limiting the refrigerant charge in HVACR products that can leak into a confined space. Unfortunately defining the space or room volume is not a straight forward exercise in real life situations. Defining the height of a room can be simple enough, but defining the effective floor area of the room to calculate the room volume can be quite difficult, time consuming and variable depending a large number of factors including obstacles or restricted spaces in the room. Factors to consider are room fill, adjacent spaces, leak release height and natural convection to name a few.This paper will describe an effective approach to use to calculate the room area. Computational fluid dynamic (CFD) analysis was performed to support the justification for the methodology in this paper. Different approaches will be described for determining the room area for unventilated and ventilated spaces and demonstrate that areas above partition walls, drop ceilings, or ductwork connecting rooms shall not be considered as connecting the adjacent spaces. Natural ventilation as well as forced air circulation will be defined to determine the maximum floor area to consider for calculating the room volume. A majority of the work was conducted to simulate refrigerant leaks from a wall mounted unit at height of 1.8 meters (5.9 feet). A few additional points were run at 0.6 meters (2 feet) to validate the methodology but a detailed analysis was not conducted for these scenarios. Various safety factors will be considered based on the application to determine the maximum refrigerant charge allowed for using ASHRAE Standard 34 Class A2L flammable refrigerants. Maximum refrigerant charges for a large number of ASHRAE 34 classified refrigerants will be summarized for comparison purposes at various LFL endpoints.