Case Study: TOTO

Company Overview

Client name: TOTO LTD. 
Industry :Production and sale of housing equipment, especially for water using equipment such assanitaryware, integrated toilets, spray seat and integrated bathrooms
Profile    :2-1-1 Nakashima, Kokura-Kita Ward, Kita-Kyushu City, Fukuoka Prefecture, Japan
Business challenge:Conformity to IEC 60335-1 with functional safety evaluation
Our solution  :Evaluation testing and certification service regarding IEC 60335-1

「Pursuing safety to protect you in compliant to Standards for Household and Similar Electrical Appliance - Safety(IEC 60335-1)」

Business challenges

Innovation starting with toilets

TOTO, a leading company in toilets and spray seat combines traditional craftsmanship with electrical and mechanical features to achieve diversified functions of a sanitaryware. To further breakthrough in the world market, TOTO’s global development and values go beyond design ability, functionality and product safety.


Offering our safe and secure WASHLET® to the world

Conforming with IEC 60335-1 and acquiring the certification have been challenging. TOTO’s goal of achieving high level of product safety makes the Protective Electronic Circuit (PEC) indispensable.

According to IEC 60335-1, design and evaluation based on functional safety in connection with the product introduction are required. However, there has been no case of development fully considering PEC and functional safety in products having the standard mentioned above. TOTO selected TÜV SÜD as a third-party certification authority and a partner to work on unprecedented development, and succeeded in creating new product from scratch. This was a pioneering instance in the world.

TOTO acquiring TÜV SÜD certification for their product not only provides a platform for expansion on the world stage but also highlight their conformity with global safety standards.

Creating safe and secure products accepted worldwide

Mr. Shinji Okano, a group leader of the WASHLET® Quality Assurance Division, said: “That is why conformity with IEC 60335-1 was a major premise.”

A spray seat is a product that requires extremely highsafety. The warm water that is heated to wash users’ bottom must safely wash them while keeping the temperature high enough for the user and low enough for safety.

TOTO enhances the Japanese toilet culture to the world through accelerated global development. Regarding product safety as one of the most important matter, TOTO has developed products compliant to the IEC 60335-1 safety standards of shipping destinations such as the USA, China and South Korea.

However, a third-party certification authority provided us with unexpected information in 2013, saying: “TOTO’s spray seat which uses instantaneous warm water may possibly fail to conform with IEC 60335-1 in the near future.”

Our solution

Strict safety standard for PEC

This information had a great impact on TOTO. If TOTO’s product does not comply with IEC 60335-1, TOTO will not be able to move forward with their international strategy.

The investigation advanced and the background gradually became clear. While safety standards are becoming stricter, IEC 60335-1 has also been updated with stricter safety requirements.

A spray seat is usually equipped with a solenoid valve and a protective circuit that controls the valve opening and closing. If the water temperature exceeds the normal temperature, it stops water from being discharged, preventing the user’s bottom from being burned by hot water. TOTO uses a semiconductor integrated circuit (comparator circuit) with excellent response as the protective circuit that uses an instantaneous-type warm water supply method.

We discovered that the semiconductor integrated circuit has been multiplexed as provision against breakdown but the configuration failed to satisfy new safety standards.

In accordance with the evaluation process based on the revised IEC 60335-1, the protective circuit comprised of electronic components was clearly defined as a Protective Electronic Circuit (PEC) in particular and required to offer a higher safety level compared with a protective circuit, which is composed of discrete single element components. 

This revised IEC 60335-1 accordingly influenced the design sites of the household appliance industry. Even the advantage of PEC composed of semiconductor integrated circuits such as IC and other components is surrendered and a method of composing of discrete components is selected to priortise conformity with IEC 60335-1 regarding household electric appliances being equipped with PEC).

「For safe and secure products that are acceptable worldwide, conforming with IEC 60335-1 was a major premise.」

Pursuit of high safety to the absolute extent possible

TOTO did not consider the trend of using discrete components for the protective circuit. TOTO was determined to conform with IEC 60335-1 while using semiconductor integrated circuits with excellent response.

“We considered alternate solutions carefully. After that, we determined our policy of using PEC,” Mr. Koji Mine, the chief engineer of the Electronics Engineering Division, A spray seat compliant to IEC 60335-1, was created from persistent manufacturing consciousness that pursues high quality and safety. TOTO philosophy is shown at the TOTO Museum that was established as a commemorative event of the 100th anniversary. looked back on the determination at that time.

A spray seat is originally classified, depending on the warm water supply method, into two types: instantaneous types and warm water storage types. TOTO has used a configuration equivalent to PEC for instantaneous type products. The instantaneous type warms water at the moment of washing the user bottom and jets the warmed water through a nozzle. The instantaneous type is superior in downsizing over the other warm water storage type, resulting in enhancing toilet seat design ability and functionality.

Start from scratch

They decided to develop PEC compliant to ICE 60335-1 but the path to practical implementation was always challenging. The difficulty came from the use of PEC actually needing design and evaluation considering the concept of functional safety, which had not been required. “We lacked knowledge and experience for unprecedented technological development. We had no internal or external examples to refer to. We really needed to create a product from scratch,” Mr. Yasuhiro Matsuda, Electronics Engineering Division, looked back on those days.

When starting the development, they needed to start by understanding the content of the standard including what kind of configuration is regarded as PEC in IEC 60335-1 and what kind of safety evaluation test is required. In addition, they were not aware that the design and evaluation of PEC needed to be based on the concept of functional safety.

TOTO selected TUV SUD as a partner to overcome this difficulty. The valuation of their technology and responsibility increased through the technical communication about ongoing tests and certification. They expected us to bring the driving force of this project from scratch. 

「We went back to the starting point of TOTO, following our policy of thoroughly pursuing safety, and our development staff united under the idea of using PEC.」

Business benefits

Acquiring certification of perfect conformity

TUV SUD held workshops with TOTO to explain standards and implemented preliminary evaluations to repeat the information thorough discussions. TOTO entrusted TUV SUD on the judgment of design and specifications nonconformity. TOTO went back to the standards whenever nonconformity was presented, and deepened our interpretation and understanding. Mr. Matsuda said: “TUV SUD will evaluate the work so that PEC perfectly conforms with IEC 60355-1 and the proof will be incontrovertible to whoever views it. I believe TOTO understood a lot through discussions, because the development of IEC 60335-1 compliant to PEC was extremely advanced work.”

TUV SUD determined through discussion with TOTO that PEC should be equipped with a safety circuit using a comparator circuit and also a microcomputer and software to detect breakdown. In this case, the document attached to IEC 60335-1: software evaluation (Annex R: Software Evaluation) is necessary. This evaluation was in light of functional safety. After understanding the next steps, TUV SUD introduced the concept of functional safety into the design and evaluation processes.

TUV SUD has a wide range of experience regarding evaluation based on functional safety. TUV SUD has handled many certifications and evaluations related to functional safety in the industrial equipment market and offers excellence and project like TOTO’s to advance smoothly.

Final practical implementation of PEC

TOTO came out with the NEOREST NX in 2017, which was also TOTO’s 100th anniversary. NEOREST NX is a flagship model manufactured by merging sanitaryware created by craftsmanship with electrical and mechanical features, achieving advanced safety and diversified functions.

This is the practical implementation of IEC 60335-1 compliant to PEC. This model is the first spray seat whose safety and reliability have been improved to an even higher level; this also places this model at the front of the IEC 60335-1-related household electrical appliance industry.

TOTO will utilise this result as driving force for global development. TOTO has acquired CB certification, which is required to apply for safety certifications in each country, through TUV SUD.

Global development model equipped with certified product

The total WASHLETR shipped have exceeded 40 million since its commercialisation 45 years ago. They are moving forward with the addition of this certified product for global development.

Add value. Inspire Trust.

TUV SUD is a trusted partner of choice for safety, security and sustainability solutions. It specialises in testing, certification, auditing and advisory services. Since 1866,

the company has remained committed to its purpose of enabling progress by protecting people, the environment and assets from technology-related risks. Through more than 24,000 employees across over 1,000 locations, it adds value to customers and partners by enabling market access and managing risks. By anticipating technological developments and facilitating change, TUV SUD inspires trust in a physical and digital world to create a safer and more sustainable future.

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