Non-prescriptive design within fire engineering is becoming more prevalent as buildings get taller and more complex. This necessitates the increased use of reliable deterministic predictions, typically computational fluid dynamics-based models. Driven by time constraints, modellers are required to limit the domain to reduce wall time. This ignores the two-way coupling of a fire and a total building system which could embody risk to life. One way to address this risk is the use of coupled hybrid modelling to expand the domain, explicitly quantifying risk-related quantities in the far field whilst maintaining practicable wall times. Fire Dynamics Simulator (FDS) version 5.5 opened the door to coupled hybrid modelling within FDS and introduced the HVAC network submodel. Until FDS version 6.5.3, the submodel did not account for transient transport or mass storage. In this work, a new transient transport and mass storage subroutine has been introduced into HVAC which is available in FDS version 6.5.3 onwards. The relevant conservation equations and numerical solution are described. Successful verification cases are presented for various arrangements to test the implementation of the solution scheme. To demonstrate the benefits of the new method, a fire engineering test case is presented. The test case illustrates the potential risks contained within the pre-existing coupled hybrid modelling method. These risks include unrealistic predictions of hot layer height and head height temperatures and visibility. The test case demonstrates that the new coupled hybrid modelling method address these shortcomings and could form part of a most robust fire safety engineering solution. Based on experimental benchmarking exercises, recommended model correction coefficients are put forward. The new model implementation can be used by designers to quantitatively examine the fire hazard embodied within the two-way coupling of a fire and a total building system.

随着建筑物越来越高和越来越复杂，消防工程中的非规范性设计正变得越来越普遍。这就需要增加使用可靠的确定性预测，通常是基于计算流体动力学的模型。受时间限制的驱使，建模人员需要限制域以减少墙面时间。这忽略了可能体现生命危险的火灾与整个建筑系统的双向耦合。解决这种风险的一种方法是使用耦合混合模型来扩展域，在保持可行的挂墙时间的同时，明确量化远场中与风险相关的数量。Fire Dynamics Simulator（FDS）5.5版为FDS中的耦合混合建模打开了大门，并引入了HVAC网络子模型。在FDS 6.5.3版之前，该子模型没有考虑瞬时运输或大量存储。在这项工作中，HVAC中引入了一个新的暂态运输和大容量存储子例程，该子例程可从FDS 6.5.3版开始使用。描述了相关的守恒方程和数值解。提出了各种安排的成功验证案例，以测试解决方案的实施。为了演示新方法的好处，提出了一个消防工程测试案例。测试案例说明了预先存在的耦合混合建模方法中包含的潜在风险。这些风险包括对热层高度，压头高度温度和可见度的不切实际的预测。测试案例表明，新的耦合混合建模方法解决了这些缺点，并且可以构成最强大的消防安全工程解决方案的一部分。在实验基准测试的基础上，提出了推荐的模型校正系数。设计人员可以使用新的模型实现来定量检查火灾和整个建筑系统的双向耦合中体现的火灾隐患。