Conference Agenda

As cities expand vertically, high-rise multi-unit residential buildings (MURBs) are becoming more popular forms of urban housing. Elevators are an essential part of vertical living but are also detrimental to building performance when it comes to uncontrolled airflow. Unlike stairway doors, which can be weather-stripped using conventional solutions, the mechanical nature of elevator doors makes standard air-tightening methods impractical. However, ensuring airtight elevator shafts in MURBs is essential for energy efficiency, occupant comfort, and safety. The goal of this paper is to demonstrate the impact of elevator shaft airtightness on building performance and provide potential solutions. Elevator shaft airtightness is crucial to energy efficiency and comfort in MURBs as these shafts can act as vertical conduits for smoke, fire, and conditioned air. Typical values for elevator shaft airtightness are presented, then these are compared with existing airtightness requirements, focusing on regulations related to smoke and fire safety, to highlight the importance of compliance with established standards. Existing solutions to improve elevator doors include vestibules which are widely used in commercial buildings but less so in residential buildings and cannot be implemented on all floor plate configurations due to the space requirement. Adopting different solutions such as fire curtains, high-speed roll-ups, and bi-fold doors could offer improvements without encroaching on the current common area floor space. This paper emphasizes the need for improved elevator shaft airtightness in MURBs and illustrates how improving elevator shaft airtightness can enhance energy efficiency, occupant comfort, and safety. Further research efforts should focus on investigating the feasibility of applying some of these alternative solutions to improve elevator door airtightness.

The issue of leakage in air distribution systems is one of the most underappreciated efficiency improvement opportunities, even though potential improvements are significant. One of the main reasons for this lack of awareness lies in the current ineffective practices for determining and addressing the energy consequences due to poor tightness. The airtightness of ducts is generally only evaluated based on classifications (e.g. leakage class or seal class), which are in turn used to estimate duct leakage flows during normal operation using an assumed operating pressure, and a fixed flow exponent of 0.65. This paper presents technical arguments for why it is worthwhile to characterize duct leakage with measured flow exponents and operating pressures, or with direct measurements of leakage flows during normal operation. The focus is non-residential buildings, for which there are large variations in duct pressures during normal operation, between different duct sections, and between testing/classification values and normal-operation values. Experimental evidence is presented to show that the current methodology is not suitable for describing the real behavior of ductwork. Two alternative methodologies are described, both related to expressing leakage in percentage terms with respect to the nominal flow rate. The difference between the two indexes is that the first one utilizes the estimated leakage at working pressure, the other indicates the maximum pressure at which the system can work in order not to exceed a predetermined percentage leakage value.

Duct air leakage tests -DALT- carried out on air systems today are carried out according to the procedures prescribed by specific International Standards. All these Standards, without exception, refer to a model that estimates leakage as a function of a leakage coefficient (f) multiplied by the leakage area value (A) and the static overpressure value elevated to an exponent n assumed constant and equal to 0.65. This model is a simplified form of a more general model that also requires determining the leakage exponent n.

Within certain limits, the simplified model fulfills the classification requirements but does not prove reliable for the analysis of leaks under operating conditions and, thus, for verifying the increase in energy consumption.

For such purpose, the application of the full model appears to be necessary; this requires the identification of a different test procedure capable of obtaining the information needed to determine not only the f- value but also the n - value.

The paper is focused on the proposal of a procedure useful for the characterization of the full model as well as a methodology for calculating the f and n parameters borrowed from that currently applied for the characterization of air leakages in buildings. Finally, the paper proposes a method to transfer the results obtained by the new procedure back to the information useful for classification, thus allowing the old procedure to be fully replaced without losing the applicability of the existing standards.

The methodology was applied to a real system and the values were identified.

The procedure presented was developed with the aim of being able to carry out the measurements using the same DALT instruments used to date without requiring replacement.