Fuji Electric Cable Co., Ltd., boasts one of the largest market shares nationwide in the field of fireproof cable manufacturing and sales. In response to fire-related disasters from 1965 to 1985, in an about face from its original business of bind wire and vinyl insulated cables, the company shifted the focus of its efforts to manufacture, research, and development of fireproof cables. With the vision of protecting countless people from life-threatening fires in facilities, the company, which had won out over fierce competition in the industry, finally succeeded in developing a “1-hour fireproof cable” in 2021. And it is a fact known only to those in the know that Okabe Mica was the main partner that has supported the manufacture of fireproof cable by Fuji Electric Cable. We invited supervisors from both companies who have been instrumental in establishing this unshakeable partnership that has spanned so many years, to tell us about the unknown episodes and hardships that lie behind the development known only to those involved and the outlook for the future.
FUJI ELECTRIC CABLE CO.,LTD.- Hideaki Okazaki
Kofu Factory Former Manager
Production Engineering Department
Yoshikatsu Motegi
Electric Power Technology Section Chief
Isehara Factory
Production Engineering Department
- Okabe Mica Co., Ltd.
- Takeo Okabe
Director
Sales Management Manager
Tetsuji Harada
Manager
Molding Manufacturing Department
Molding Division
Background to how both companies set themselves the same goal of “developing a next-generation fireproof cable”
Mr. Okazaki:
Although we have achieved a track record as the top market share holder in the field of fireproof cable manufacture, manufacturing fireproof cable was not our original business. Our original business at the time of the company’s establishment in 1951 was bind wire and vinyl-insulated cable research and development. Rather than cable with special functions, we simply refined our technology in the field of manufacturing “wire that conducted electricity” and thus continued to grow steadily. As these efforts bore fruit, it seems that, with the advent of the Heisei era beginning in 1989, we were fortunate enough to find ourselves in an environment where we earned the patronage of companies representative of Japan who were major players in the infrastructure business.
Okabe:
To sum up, your company enjoyed dynamic growth, didn’t it? And, in the years from 1965, when the company was thriving, fires occurred one after another in places such as hotels and department stores. One such disaster, we found particularly tragic was the Taiyo Department Store fire in Kumamoto Prefecture as our head office is in Kyushu.
Prompted by these disasters that cost so many lives, installation and technical standards for firefighting equipment for the prevention of fire, which had, up to this time, had been inadequate, were updated under the Fire Services Act. One of the items targeted by the update was fireproof cable which, up to this point in time, had been regarded as a rather minor item. However, our company, a manufacturer of mica materials with heat-resistant properties, felt a strong sense of mission, and came to a firm resolve to tackle the situation. What steps did Fuji Electric Cable take at the time?
Mr. Okazaki:
From what I’ve heard, apparently the president at the time was also aware that the demand for fireproof cable would grow, given the social conditions at the time, because the revision of the Fire Services Act targeted large-scale facilities such as hotels, department stores and hospitals, and came at a time when demand for large-scale buildings was growing.
Okabe:
After investigations into the disaster in question, it was reported that that, if equipment that played an important role on evacuation routes such as emergency lighting, sprinklers and elevators had functioned properly to the end, even if a fire had broken out in the building, it may have been possible to keep damage in check. From the standpoint of firemen who carry out rescue work too, it is important that facilities on escape routes keep functioning properly.
Mr. Okazaki:
That’s right. In March 1969, the Tokyo Fire Department established “test standards for fireproof cables for exposed wiring used in high-current circuits for emergency power supplies of 600V or less,” and this marked the beginning of development of fireproof cables. In June 1972, after acquiring certification from the Fire and Disaster Management Agency, the first step was taken with the start of the “SHFA” fireproof cable manufacturing factory.
Fireproof cable manufacturing business started by Fuji Electric Cable thanks to the company’s foresight
Okabe Mica approached Fuji Electric Cable in response to the company’s whole-hearted devotion to development
Mr. Okazaki:
Be that as it may, our company had no technologies to develop cables with special functions. It seems that the company especially struggled to devise processes for crimping calcium carbonate powder on conductors using molding devices. The cable had a fireproof layer structure that made it necessary to prevent the escape of powder produced by longitudinal fitting of glass cloth, a material resembling a glass net which is highly heat resistant and flexible, and horizontal winding of glass yarn. I have heard that it required a lot of skill to realize stable fireproof performance of the cable. Although using mica tape was an option, in those days, it was believed that there were no products available that provided the necessary quality. Perhaps you know something about this, Mr. Okabe.
Okabe:
Let’s ask a veteran from our company, Mr. Harada.
Harada:
I think this is probably a disadvantage that was pointed out with the first fireproof cable. This was a time when the occurrence of the “back phenomenon” where mica and glass adhere was a problem. Our company tried measures to prevent this by adhering mica powder, but this was not sufficiently effective, and changes were made such as substituting glass for film, but the back phenomenon continued to be a problem for about ten years from 1975 to 1985. During this period, we tried all kinds of measures such as reviewing materials such as adhesives and glass cloth, improving manufacturing conditions and changing methods of evaluation. In the first place, because mica degrades with time, it is extremely important to prove quality at the stage where products are fresh off the line.
Okabe:
Changing methods of evaluation is important. Because the rate of degradation of mica after delivery accelerates depending on storage conditions and duration. At the time, the reasons for this were unknown, and we were searching for the causes.
Mr. Okazaki:
Hearing it again, I feel that the quality of cables now is the result of efforts made down through the generations. I was assigned to development in 2005. At the time, our company was doing its best to reduce the cost price of mica tape as it was trying to survive and win out as a cable manufacturer. At that time, mica quality had already stabilized and what we have been talking about feels like the distant past. In 2005, our company’s products were expensive and some of our customers found them to be too thick and hard to handle. In an effort to remedy this, we were developing products with the aim of lowering prices and making cables slimmer and easier to use. Our goal was to “develop a cable that withstands a temperature of 840 degrees for 30 minutes.”
Okabe:
It was just about then that Mr. Okazaki approached us. Thanks to your very clear description of the type of product you wanted to manufacture, we were able to ascertain matters such as the mica tape thickness and level of quality required. I believe that it was your precise disclosure and provision of information that enabled us to make a proposal as close as possible to requirements. There aren’t many manufacturers who are so helpful, and I was happy to be able to do whatever I could to propose a product specially for Fuji Electric Cable.
Mr. Okazaki:
I’m sorry to have made a request that may have caused a drop in Okabe Mica’s sales. Even within the company, we were looking for anything and everything that we could do to improve the manufacturing process. We had no evaluation equipment, so we tried approaches such as calculating theoretical coefficients of friction, and whether we could use pine resin as a non-slip measure.
Motegi:
The “cable capable of withstanding a temperature of 840 degrees for 30 minutes” that we succeeded in developing boosted our market share to 50% for a time, a really excellent achievement for our company.
Harada:
After thinking about what we could do to reduce manufacturer’s development costs, we considered the approach of supplying products after in-house fireproof evaluation and quality assurance. This is a simple method of evaluation using an electric furnace, which we called the SP method. It took ten years to establish this method. Evaluation using the SP method enabled us to make major contributions in terms of cost and quality both for companies who had their own fireproof testing furnace, needless to say, and companies who did not.
Mr. Okazaki:
Thanks to Okabe Mica’s efforts to improve their evaluation performance year after year, we have been able to make many decisions relying on their evaluations, and, as a result, our development costs have been reduced. Also, after many subsequent trial prototypes and discussions, MAT-1PMS is the mica tape we have succeeded in developing. With this successful development as the starting point, our market share has steadily grown, we have now achieved the top share for fireproof cable in the country. And, with this as a springboard, we have strengthened the relationship between our companies as a true open technical collaboration.
Since then, mica tape has evolved in parallel with fireproof cable and we asked Okabe Mica to work with us as a matter of course to develop a 1-hour fireproof cable.
Development of a 1-hour fireproof cable that will become the new norm in industry
Motegi:
In developing the new one-hour fireproof cable, we wanted to ensure one-hour fireproof performance without any major changes in specifications or price from the 30-minute fireproof cable. This was to reduce the burden on our customers as far as possible. As a result, we succeeded in developing a groundbreaking cable that can withstand a temperature of 925 degrees for sixty minutes compared to the existing cable, which can withstand a temperature of 840 degrees for thirty minutes, but this was no ordinary undertaking. The biggest challenge was that, if we used the existing mica tape, we would have to increase the number of sheets used and thus the thickness. This meant that we were unable to take any substantial approach, and we continued to see no major improvements in properties as we repeatedly conducted experiments using materials such as synthetic mica. This prompted us to start on the development of a new mica tape.
Harada:
Thinking that approaches such as simply increasing the thickness of the mica would be ineffective, we turned our attention to a material called nano silica. Nano silica has functions that improve the insulating performance of mica. However, because it was a new material, there were no technologies or devices available that would make even coating possible, and this caused us problems during the development process, but somehow, we succeeded in achieving our goal.
Motegi:
At the outset, we thought of trying to use the existing mica tape and conducted trials of approaches that were really not possible with the existing process, but the results failed to pass fireproof testing, leaving us at a loss. Then we turned to Okabe Mica for advice, and they supplied us with mica tape coated with nano silica. This enabled us to move ahead with development comparatively smoothly.
Mr. Okazaki:
Okabe Mica’s evaluation method is also alive here. I believe that we already mentioned that a test method had been established, and the results of this method enabled us to ascertain elements such as the performance and possibilities of the new tape to a certain extent. I believe that the prospect of success that we saw in the enhanced know-how we acquired from experience and precision was the key to smooth progress with development.
Okabe:
I am really grateful to hear you say that. I have also learned a great deal about the importance of hypothesis and verification through our relationship with Fuji Electric Cable. After achieving the top market share, we have constantly looked at things with new points of views and frequently talked about tackling groundbreaking initiatives and creating new markets ourselves.
We jointly registered the patented technology for “cable evenly coated with nano silica” together and I see this as also being one step in such initiatives.
Continuing cooperation with singleness of purpose between the two companies
Mr. Okazaki:
Firstly, I think the tough mental stamina and tenacity that stops your company from giving up and strong spirit of tackling challenges are wonderful. And above all, I admire the way all your employees in the workplace understand this spirit and pull in the same direction to achieve success. Also, this is the first time for me to say this to you, Motegi, but I wanted you to develop the strength to think and see things through to the end yourselves and overcome obstacles together with supervisors.
I hope that, in the future, you will continue to be a partner with whom we can work together toward the same goals, as we have this time.
Motegi:
I was so busy with development that I hadn’t realized how you felt, Mr. Okazaki (laughter).
But I strongly feel that we cleared one hurdle together to realize our development theme.
Harada:
Our young employees have also really grown through our undertakings on this occasion. I feel that it is wonderful that we cooperate and grow together. Above all, you always treat our company as a joint developer, and we have a rare relationship where we share both our joys and sorrows.
Okabe:
One big difference between Fuji Electric Cable and our company is our thinking on “entrusting tasks to others” and “giving others a chance to try.” Entrusting others requires a great deal of courage on the part of the person entrusting tasks to others. I also took a chance and decided to entrust tasks to our young employees. I am happy to say that the result was that we achieved our goal.
Mr. Okazaki:
Thank you. It really is rewarding to come up with new ideas and achieve success together, isn’t it?
Okabe:
I really share the Fuji Electric Cable’s vision. In the past, Fuji Electric Cable told us that they wanted to become the world’s top company in the field. This made us want to support their goal and when they succeeded, we shared in their joy as if it was our own company, and this kind of connection between us formed naturally.
This feeling also spread throughout our company, and everyone cooperated with what I wanted to do.
With Fuji Electric Cable becoming the top company in the industry, they are pursuing new visions. They share these goals with us above and beyond our standpoint and this is a driving force for us. We want to do everything we can in the future too so that Fuji Electric Cable will feel that we are always by their side.
Click here for information on products introduced in this article.
The length of time cable is capable of conduction in a fire has increased from thirty to sixty minutes.- The outer diameter, weight and handling characteristics of the previous product have been retained.
- Because polyolefin material is used in the sheath, no harmful substances such as dioxin or halogen gas are produced if the cable burns.
- The cable produces little smoke if burned and is also provided with properties to prevent the production of harmful hydrogen halide gas or corrosive gases.
- Products are compatible with current bulletins and standards and can also be used in the same installation environment as previous products.
