The sensor system of the automatic revolving door that crushed a 6-year-old boy to death Friday in Tokyo’s Roppongi Hills complex had been adjusted upward to respond only to objects standing 135 cm or higher, police sources said Monday.

It is believed the sensor on the ceiling above the door did not activate to stop the door from revolving because it failed to detect the victim, Ryo Mizokawa, who was 117 cm tall, they said.

The accident occurred at the Mori Tower building in the popular business and entertainment complex.

Sanwa Tajima Corp., the distributor of the door, said the sensor had initially been set to detect objects of 80 cm or higher.

The setting appears to have been changed after consultations involving Mori Tower and Sanwa Tajima employees. The apparent aim was to prevent the door from stopping unnecessarily, according to the sources.

The change was made after the door became easier to stop by sensing a 90-cm-high safety fence put in front of the door following an accident Dec. 7, when a 6-year-old girl was hit by a revolving door at Roppongi Hills and sustained injuries.

The sensor is normally adjusted by Sanwa Tajima at the request of the operator of Mori Tower. During a routine inspection of the revolving door on Dec. 3, the sensor was confirmed to have been set to detect objects 80 cm or taller, according to the company.

There was another sensor at the door to sense an object 15 cm in height. But it apparently did not detect the boy as was leaning forward as he rushed into the door, they said.

The boy’s family held a funeral Monday in Suita, Osaka Prefecture, where they live.

Toshitaka Takayama, president of Sanwa Shutter Corp., the parent company of Sanwa Tajima, went to the funeral hall. But the family refused to allow him to attend the service.

“I came here to pray for his soul and convey my condolences to his parents, but I was not allowed to,” he told reporters. “I have decided to do my best to prevent a recurrence of the accident.”

Safety rules planned

Staff report The Land, Infrastructure and Transport Ministry will soon craft safety guidelines for revolving doors, vice minister Noriyuki Kazaoka said Monday.

The move was prompted by a fatal accident Friday at the Mori Tower building in the Roppongi Hills complex. A 6-year-old boy was killed after getting his head jammed in the revolving doors, whose sensors apparently failed to detect him.

Kazaoka said he hopes the ministry can compile a final report or at least an interim report on the guidelines within three months.

“Since revolving doors of this kind are relatively new and we had never received any reports of fatal injuries, there are no legal safety standards regarding them,” Kazaoka told a regularly scheduled news conference.

The ministry will set up an advisory panel that will consist of experts as well as officials from manufacturers of automatic revolving doors, building management companies and ministries, including the Ministry of Economic, Trade and Industry Ministry, according to Kazaoka.

The ministry has started a survey and is gathering information to get a clear grasp of the actual situation.

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