In disaster-prone Japan, earthquake resistance is vital to prevent buildings from collapsing when a powerful temblor hits, and builders and seismic reinforcement providers have repeatedly given assurances about the safety of their structures.
So when quake damper producer KYB Corp. admitted in October to falsifying data for its products aimed at improving earthquake resistance and installed in nearly 1,000 buildings across Japan, questions emerged: Are our homes and office buildings really safe?
Here is a look at those and other questions concerning the data falsification scandal and ensuing safety issues.
Why did KYB make headlines?
Established in 1919, KYB is known as one of the world’s largest producers of shock absorbers.
But last month its name made headlines for all the wrong reasons. In October, KYB admitted to having falsified data for two types of shock absorbers: those used as seismic isolators and others mitigating seismic energy in buildings.
“Such practices have sparked fears among property owners and users, and damaged public trust in the safety of buildings. It is extremely regrettable,” infrastructure minister Keiichi Ishii said in criticizing the damper-maker at a news conference on Oct. 19.
The data manipulation of damper quality inspection records was discovered by a KYB worker in early September. This prompted the company to disclose the revelation to the public.
The dampers were produced by KYB subsidiary Kayaba System Machinery Co. at its factory in Tsu, Mie Prefecture. KYB presumes the data fabrication occurred between January 2003 and this September.
What kind of technology is used to prevent buildings from collapsing in earthquakes?
Builders use three quake-resistance technologies.
The most conventional one is the reinforcement of pillars and joints in a structure so that the building can withstand quake energy.
The other type is aimed at preventing ground vibrations from being transferred to the building. It not only prevents the building from being damaged but also prevents furniture and equipment from moving or falling over.
The third one is aimed at controlling vibrations, which are caused not only by earthquakes but also strong winds. Such structures are reinforced with dampers installed on building pillars and joints.
KYB dampers are used in the second and the third type.
What role do KYB oil dampers play in earthquake resistance?
When an earthquake occurs, damping or resistive force is needed to stop buildings from shaking.
KYB dampers serve that function. They are based on a hydraulic oil mechanism that in the event of a major quake triggers resistive force.
These dampers are used as seismic isolators and are installed between the building’s structure and the ground to prevent transmission of vibrations to the building.
But since seismic isolators installed at the base of a structure cannot stop vibrations already transmitted to the building, builders also install dampers in joints, beams and walls to disperse quake energy and reduce the deformation of buildings. Such features are needed especially in hotels and hospitals.
Other technologies used in seismic isolation include rubber and steel bearings, which restore buildings tilted by quakes to their previous position, and friction dampers with moving parts that slide over each other during strong temblors.
But a land ministry official in charge of certifying such products said that over the past decade, oil dampers, including KYB’s, have been enjoying growing popularity and builders often rely on such technology in their designs because the dampers are effective in frequent quakes.
According to KYB research data, in fiscal 2017 KYB held a 45 percent market share of seismic isolation shock absorbers in Japan.
What’s wrong with the KYB dampers?
KYB falsified the values of the damping force, which was insufficient or excessive, for 499 seismic isolators in documents submitted to the land ministry when applying for certification, which is mandatory for such products.
At the KYB crisis team set up after the scandal broke, an employee who declined to be named said by phone that the firm had failed to retest products that did not conform to requirements and tweaked records so they looked like the dampers met the specifications.
Other products had damping performance within the range allowed by the ministry but failed to meet customer specifications.
KYB said that of the 10,359 seismic isolation dampers sold up to September, 7,537 could have been affected by the falsification and 3,331 vibration-absorbing dampers that were sold between 2000 and 2018 could also be faulty.
The ministry’s guidelines are based on the Building Standards Act, which specifies rules on methods to calculate a building’s stability, strength and rigidity and parts used in those structures.
How will this scandal impact building safety?
KYB assures that buildings with faulty shock absorbers won’t collapse even in a quake of the highest level on the Japanese seismic intensity scale, which ranges from zero to 7.
The firm’s claims are supported by a study by independent experts in construction who, following KYB’s data falsification revelations and on the land minister’s orders, recalculated quake-resistance in seven buildings with KYB dampers having the most deviated damping force.
“Our dampers are used nationwide and even in regions affected by strong quakes, including the Tohoku earthquake (the Great East Japan Earthquake in 2011), there were no reports of major damage or collapsed buildings,” the staffer said.
“There’s no need to hastily leave these buildings, fearing for one’s life,” said the ministry official in charge of the validation of quake-resistant structures.
The KYB employee admitted that dampers with resisting force exceeding the required values may cause buildings to sway more heavily and jerk, which could cause cracks in the buildings. On the other hand, shock absorbers with insufficient damping force may fail to stop vibrations, he explained.
Koichi Kusunoki, a professor at the University of Tokyo’s Earthquake Research Institute, noted that buildings are not really designed to withstand all earthquakes.
“They’re designed to collapse in a safe way, not to avoid all possible damage,” he said. He explained that the Building Standards Act allows for deflection to a certain degree.
He noted, however, that KYB “conned people into believing their quake-resistance technology is reliable” and this falsification may lead to civil actions against KYB.
“If a building has been designed based on the damping technology, the whole resistance becomes dubious when parts that were supposed to reduce quake energy don’t meet requirements,” he said.
Kusunoki said that replacement of faulty dampers may require destroying parts of buildings. He was also concerned about the risk of damage to buildings if a strong quake strikes when the building is raised to replace the seismic isolators.
What facilities have been affected by the scandal?
KYB confirmed its dampers in question have been installed in 1,046 buildings and facilities across Japan.
As of Nov. 9, the firm falsified data for base isolators in 894 structures, with the largest number in Tokyo and Osaka prefectures — mostly housing facilities, medical institutions and office buildings.
Faulty vibration absorbers, meanwhile, have been used in 80 buildings, mainly in Tokyo.
KYB has disclosed the names of around 90 buildings, including the Tokyo Metropolitan Government buildings, the Kanagawa and Osaka prefectural government buildings, the Yokohama Municipal Government building, and, ironically, the land ministry’s office building.
Other facilities with questionable dampers include NHK’s facilities, Tokyo Skytree, as well as the Olympics Aquatics Centre and Ariake Arena to be used for the 2020 Games.
Some condominiums in Taiwan may also be affected.
What measures are being taken to address this crisis?
The government ordered KYB to recalculate quake-resistance in all buildings with dampers in question by the end of the year. These procedures, including validation, will be handled by independent experts.
KYB has been told to replace all dampers that don’t meet the country’s specifications.
It remains unknown if dampers used in several hundred other facilities nationwide are legally nonconforming. But if KYB’s records don’t prove otherwise, those dampers will be deemed faulty and KYB will have to replace them, too. KYB may also need to replace dampers that didn’t meet client specifications.
KYB is also checking whether the data falsification took place at its subsidiaries and affiliated companies. KYB has 13 companies, including sales outlets in Japan, and 35 in Asia, the Americas and Europe.
But despite KYB’s swift response to the problem, experts say the solution to the crisis is nowhere in sight.
“Replacing faulty dampers in just one building may take months,” as there are bureaucratic procedures involving recalculating data for quake-resistance in each building by independent experts, said Kusunoki.
Kusunoki explained that if any construction-related laws were revised after KYB obtained certifications for the said dampers, buildings with faulty dampers will be deemed unfinished and it may turn out they don’t comply with new laws or amendments.
The misdeeds have resulted in KYB’s net loss of some ¥12 billion for the half year that ended on Sept. 30.