Elevator Codes

Ning Ding, Tao Chen, Hui Zhang

Zuiyuan Guo, Guangquan Xiao, Jianhong Du, Wei Cui, Bing Li, Dan Xiao

Residents have to use elevators to leave and enter their high-rise apartments frequently. An elevator car can easily spread respiratory infectious diseases, as it has a confined and small space. Therefore, studying how elevator operations promote epidemic transmission is of importance to public health. We developed an infectious disease dynamics model. First, we used homemade codes to simulate the operating state of an elevator and the dynamic process of infectious disease transmission in an apartment building due to elevator operations. Second, we analysed the temporal distribution patterns of infected individuals and patients. Finally, we validated the reliability of the model by performing continuous-time sensitivity analysis on important model parameters. We found that elevator operations can cause rapid spread of infectious diseases within an apartment building. Therefore, it is necessary to enhance elevator ventilation and disinfection mechanisms to prevent the outbreak of respiratory infections. Moreover, residents should reduce elevator use and wear masks.

S. Huan, Ayoung Yun, Ervin Cui

In 2009, the International Building Code (IBC) introduced a new requirement for an additional exit stair or evacuation elevators in buildings (except residential buildings) over 420 ft. (128 m) tall. This new requirement has emerged as a critical innovation in occupant evacuation in supertall buildings, offering the potential for faster egress during emergencies. In the 2018 edition of the IBC, the analysis of full building evacuation with elevators is further required to demonstrate an evacuation time of less than 1 h. This paper examines the implementation of evacuation elevators in accordance with recent building code developments, such as the International Building Code (IBC), Chinese “General Code for Fire Protection of Buildings and Constructions” (GB 55037-2022), and the Korean Building Code (KBC). This study provides a comparative analysis of these regulations, highlighting the evolving acceptance of elevator-based evacuation methods. Since the requirements on means of egress in the codes in China and Korea follow similar concepts in the IBC, case studies of supertall buildings in China and Korea, where evacuation elevators were integrated into the overall egress strategy, are carried out to demonstrate the capability of evacuation elevators in achieving the IBC’s requirement for full evacuation within one hour. Using computer-based egress modeling, the study evaluates practical solutions for reducing evacuation times, exploring factors such as elevator capacity, speed, and coordination with traditional stairwell egress. The results suggest that, while evacuation elevators can significantly improve evacuation efficiency, achieving the one-hour target remains a challenge in complex, high-occupancy environments. The study indicates the importance of optimizing the balance between stair and elevator usage and explores the future role of artificial intelligence (AI) in enhancing evacuation systems.

Pravin M. Tipnis, Vinay G. Vaidya

Recent studies, on the airborne transmission of the SARS-CoV-2 and the new CDC guidelines confirming the aerosol transmission of the virus, make immediate attention to the airflow in elevators imperative. While several versions have been thought of for contactless rides, there is little that has been considered for lessening the anticipated viral load in the elevator car.In this paper, a two-step approach is used. The first is the risk assessment, and the second is the risk mitigation through an improved lift car ventilation design. The risk is assessed by computing the probable viral load during the journey in a lift car. It is seen that the ventilation typically provided as per the minimum permissible requirements by codes is inadequate to handle the current situation.The computations show that one-minute exposure, to a coughing high emitter in the lift car, creates a viral load to dangerous levels well above the possible acceptable level of 10,000 virus copies/m3. To come up with the risk mitigation strategies, the required ventilation in the car was computed. The main recommendation suggests the use of forced ventilation using pressure fans and 3 to 6 air changes per minute depending on the operating environment. Such a design will help us achieve our objective of bringing the density of virus copies in the lift car to an acceptable level. A properly designed ventilation system for the elevator car will benefit in both pandemic situations as well as non-pandemic situations.

P. Shanahan, Diego P. Ruiz

Biased-noise qubits, in which one type of error (e.g. $X$- and $Y$-type errors) is significantly suppressed relative to the other (e.g. $Z$-type errors), can significantly reduce the overhead of quantum error correction. Codes such as the rectangular surface code or XZZX code substantially reduce the qubit overhead under biased noise, but they still face challenges. The rectangular surface code suffers from a relatively low threshold, while the XZZX code requires twice as many physical qubits to maintain the same code distance as the surface code. In this work, we introduce a 2D local code construction that outperforms these codes for noise biases $\eta \ge 7\times10^{4}$, reducing the qubit overhead by over 50% at $p_Z=10^{-3}$ and $\eta = 2 \times 10^6$ to achieve a logical error rate of $10^{-12}$. Our construction relies on the concatenation of two classical codes. The inner codes are repetition phase-flip codes while the outer codes are high-rate bit-flip codes enabled by their implementation at the logical level, which circumvents device connectivity constraints. These results indicate that under sufficiently biased noise, it is advantageous to address phase-flip and bit-flip errors at different layers of the coding scheme. The inner code should prioritize a high threshold for phase-flip errors, while the bit-flip outer code should optimize for encoding rate efficiency. In the strong biased-noise regime, high-rate outer codes keep the overhead for correcting residual bit-flip errors comparable to that of the repetition code itself, meaningfully lower than that required by earlier approaches.