Parts maker KYB Corp. and a subsidiary falsified the inspection data of oil-type base-isolation and vibration dampers (see below) manufactured by the companies and used nationwide at such facilities as city halls and hospitals, the government has said.
According to the Land, Infrastructure, Transport and Tourism Ministry, KYB and Kayaba System Machinery Co., both based in Minato Ward, Tokyo, shipped products that did not meet the ministry’s standards. The data falsification may have continued for almost 20 years, the ministry said Tuesday.
The products, including the ones currently being investigated to confirm falsification, were reportedly used in 986 cases, including condominiums, hospitals and city halls.
The ministry said these buildings are not in danger of collapsing even in an earthquake of around 7 on the Japanese seismic intensity scale. Nevertheless, both companies have been ordered to quickly replace the affected products and find out the cause of the falsification.
Data was falsified on oil-type base-isolation and vibration dampers manufactured from March 2000 until last month, according to the ministry and KYB. The oil dampers were manufactured by KYB from 2000 to 2007, and by Kayaba from 2007 onward. A total of 7,550 of the base-isolation dampers are in use at 903 locations, and 3,378 vibration dampers at 83. The misconduct has already been confirmed in 410 of the 986 cases. The remaining cases are currently being investigated.
The data that was falsified concerned tolerance to shaking. Products that did not meet standards set by the ministry or client companies in performance testing should have been disassembled and readjusted until the data fell within the accepted range. However, the data was fabricated and submitted as test results.
In early August, a Kayaba employee reported suspicions of data falsification to a superior. Kayaba reported this to KYB, which launched an investigation, and on Sept. 19 told the ministry.
Both firms said that the testing was a one-person job. At least eight workers have admitted being involved in falsifying data, which dates back to 2000, the companies said. Data was falsified for reasons such as “to meet delivery deadlines.”
By prefecture, the largest number of affected buildings is in Tokyo at 250, followed by Osaka Prefecture at 107, Aichi Prefecture at 93 and Kanagawa Prefecture at 71.
By building type, 265 were residences, 175 were offices, 159 were welfare or medical institutions, and 109 were government buildings.
“We deeply regret that inappropriate acts were continually carried out,” KYB Chairman and President Yasusuke Nakajima said at a Tuesday press conference in Tokyo attended by both companies.
According to a private credit investigation firm, KYB was established in 1948. Its main business is manufacturing hydraulic and pneumatic equipment. In the fiscal year ending in March this year, the company logged about ¥199.3 billion in sales.
Kayaba is a wholly owned subsidiary of KYB, logging about ¥8.9 billion in sales in the same period.
Suspect parts used at some 2020 venues
In connection with the falsified inspection data scandal surrounding oil dampers manufactured by KYB Corp. and its subsidiary Kayaba System Machinery Co., products suspected of not meeting required standards have been used in the construction of some venues for the 2020 Tokyo Olympics and Paralympics, The Yomiuri Shimbun learned Wednesday.
Such suspect products have been used at the Olympic Aquatics Center and the Ariake Arena, sources said. The two facilities are both under construction in Koto Ward, Tokyo, by the Tokyo metropolitan government for the 2020 Games.
The metropolitan government will confirm whether the situation poses any safety problems through the company in charge of construction. It also plans to replace the parts with new oil dampers.
The Olympic Aquatic Center will host swimming, and Ariake Arena will host volleyball, among other events, in 2020.
“[The incident] could negatively affect the schedule of the construction of the venues. We’d like to take urgent action on this matter,” an official of the metropolitan government said.
Piston-like devices that use the viscosity of oil to soften shocks and vibrations. Oil-type base-isolation dampers are installed in basements, along with base-isolation rubber and other devices, and they help to prevent the building from shaking. Vibration dampers are installed diagonally, such as between the posts of a building.