## 4 Conclusions  
In this study, through human injury analysis, safety device operations, such as speed governor and buffer when breaking elevator wire rope, occupant's behavior, and air mat usage, were used to derive force and torque values for the injured part, and then determine the amount of impact and degree of injury to the human body. By analyzing the buffering effect of impact, the following conclusions were reached. Subsequently, we determined the amount of impulse and degree of injury to the human body. By analyzing the buffering effect of the impact, we reached the following conclusions:  
1. On cutting the elevator rope (free fall), the analysis revealed that all human body parts and joints ruptured after falling at 14 m/s from the 5 th floor to the lowest floor, confirming that comparing the amount of impact and degree of injury according to the method was insignificant.
2. Activating the speed governor safety device (1.4 m/s uniform motion) was associated with a high possibility of fracture in the ankle area in both standing cases, i.e., standing with one or two individuals, respectively.
3. Activating the speed governor safety device (1.4 m/s uniform motion) was associated with a high possibility of fracture in the neck joint area in the scenario where a single individual was lying down. However, when two individuals were lying down, there was a high possibility that a neck joint fracture would not occur owing to the buffering action of the lower body.
4. If the governor safety device was operational (1.4 m/s constant velocity motion), the air mat afforded a buffering effect to a single individual lying down, similar to that observed when two individuals were lying down.
5. In the case of an elevator fall when the governor safety device is operational, the posture of an individual lying on the lower part of the individual to be protected affords a greater buffering effect than the standing position; the use of an air mat would yield a similar buffering effect.
6. In the case of a single individual lying down when the speed governor safety device is operational (1.4 m/s uniform motion), the overall degree of cervical spine injury would be low. In addition, inadequate mutual restraints were more likely to cause cervical spine injury than instances of perfect mutual restraint.  
Although the standing person breaks his/her ankles first, and it would then be expected that the secondary impact of the body on the floor would be accompanied with  
Figure 10: The change graph of NIC values based on AIS1.  
injury risk to other parts, injury evaluation through the program can obtain a meaningful value only for the primary impact behavior, and since the secondary impact behavior cannot be calculated, there is a limit to human injury research through the program. Human injury evaluation using real people is very dangerous and almost impossible, so evaluation and development using analysis are being conducted in most of these areas. In the case of vehicles, since the experimental methods and regulations are standardized, a specially manufactured manikin equipped with various sensors instead of the human body and actual evaluation are being conducted, but in the case of elevators, it is difficult to find research related to this. This study, focusing on this point, can be said to be unique in terms of academic rigor and originality in the study of human injury evaluation in the case of an elevator fall. Since there have been few studies on human injury evaluation in the event of an elevator fall, I believe that the results of this study can be applied to future elevator airbag concepts, and it is expected that it can be used as the basis for various fields such as security aspects and safe work methods.  
This research received no external funding.  
Not applicable.  
The author declares no conflict of interest.