Internationally recognised as the symbol of Swiss precision, the Contrôle officiel suisse des chronomètres (COSC) attests to the chronometric precision of a movement and, by extension, a watch. Introduced in 1973, it is still going strong.
In 2013, the Contrôle officiel suisse des chronomètres (COSC) delivered 1,688,441 certificates. In 1976, the worst year in its records but also the same year the international chronometry standard was introduced, this figure was barely 200,000. Having weathered the quartz crisis, the COSC seems to have brands’ full confidence as they square up to a likely invasion of smart Replica Watches UK Online. What explains the success of an organisation whose test criteria and protocol haven’t changed since day one?
The COSC label presents a number of solid advantages, beginning with the very reason it exists: chronometric precision. The COSC is the Swiss application of ISO/CEI 3159 international standard, established in 1976. It sets down the seven criteria required of a chronometer and defines a protocol for fifteen days of uninterrupted testing (meaning COSC offices employ staff 350 days a year). The movement is tested in five positions – 3, 6 and 9 o’clock up, dial up and dial down – for a period of 24 hours each time. Each cycle of tests is carried out at three temperatures: 23°C, 8°C and 38°C.
The purpose of these tests is to analyse possible variations in rate, in other words if the movement runs fast or slow in any of these positions, to then calculate a mean. The movement is always wound between tests to ensure it has the same power supply. Tolerances vary according to the size of the movement from -4 to +6 seconds/day for calibres more than 2cm in diameter; -5 to +8 seconds/day for anything smaller. A quartz movement must run at between -0.07 and +0.07 seconds/day. By way of comparison, a variation of -10 to +30 seconds/day for a non-chronometer-certified mechanical movement is considered acceptable.
Despite its 40-plus years, the COSC standard is as relevant as ever. “Statistically speaking, the precision of a COSC-certified movement is 99.99%,” explains COSC director Andreas Wyss. “This means that tolerated variations in rate during the testing phase represent just 0.01% of absolute precision. Precision in a wristwatch must also be seen in practical terms. There will always be an element of subjectivity in that precision has to correspond to what a person expects from their watch. From an everyday point of view, let’s just say that COSC certification guarantees that a Shopping Replica Cartier Watches is more than precise enough to ensure its wearer will never miss an appointment.” Wyss’ comment is a reminder that when the question of a standard was first raised, investigators were sent out to ask the ordinary Swiss man in the street what he considered important. Their findings would serve as a starting-point from which to draw up criteria.
COSC certification also acknowledges industrial performance. “To produce tens of thousands of chronometer movements a year, as some Swiss brands do, requires considerable expertise in development and production,” comments Andreas Wyss. “A brand has to master numerous complex parameters to achieve such a degree of precision across large-volume production.” In this case, COSC certification generally reflects a philosophy that applies at every level of the company.
Registered as a non-profit organisation, its board of directors is majoritarily composed of representatives from public authorities, hence the COSC operates without pressure from industry. Its three test centres, in Le Locle, Saint-Imier and Bienne, are fully able to handle the mass influx of watches sent for testing while maintaining complete impartiality. “So as to maintain our capacities, we are currently working with the Ecole Polytechnique Fédérale de Lausanne to improve our winding and positioning systems for greater efficiency. Our clients innovate in their business and we have to keep pace.”
COSC certification is a worthwhile investment for a brand. It costs less than ten Swiss francs to have a simple calibre tested (between CHF 5 and 5.40 for a chronograph movement, for example) whereas the COSC inscription on a dial can add up to 27% to the end price.
While results corresponding to ISO 3159 standard are perfectly satisfactory, there is nonetheless room for, and perhaps even call for, improvement. Very few Omega Replica Watches for Sale are tested as “watch heads”, that is in their finished form but without a strap, yet fitting the dial, the hands and casing the movement can cause significant tension which may have an impact on the movement’s precision. Nor does ISO 3159 standard require any test of shock-resistance after wearing, for example on a robotic arm that would reproduce human arm movements. Because ISO standards are drafted by a college of national representatives, there is no quick or easy way to modify them. Which won’t prevent the COSC board from raising the question of possible changes when it meets next year.
That there should be no great urgency reflects the COSC’s dominant position among Swiss quality labels. The context is evolving, however, beginning with the revised criteria which the Poinçon de Genève adopted in 2011. In March this year, Geneva-based laboratory Timelab unveiled the Chronometric+ Observatory certificate. This new system aims to guarantee the overall reliability of all mechanical watches that are made in Switzerland by testing factors from precision to water-resistance, power reserve and resistance to shocks or magnetic fields. At the time of writing, the system was pending two approvals from the Swiss Accreditation Service.