If the safelight made of Tungsten is used for 12/7 hours/day, what is its expected usage?

The expected usage of a tungsten safelight can be calculated based on its average lifespan, which is typically around 1,000 hours. If the safelight is used for 12 hours a day, the daily usage translates into a significant amount over time. Specifically, using it for 12 hours each day results in 84 hours of usage per week (12 hours x 7 days). To determine the number of weeks it would take to reach 1,000 hours, one can divide 1,000 by 84, which tallies to approximately 11.9 weeks. This approximates to about 3 months.

Conversely, if the safelight is used for 7 hours a day, that would equate to 49 hours a week, leading to a lifespan closer to 20 weeks, or roughly 5 months. The calculation indicates that using it for 12 hours every day would lead to its entire lifespan being utilized in less than a year.

Choosing a duration of 1 year usage accounts for variable factors, such as differences in usage patterns in practice or considerations of efficiency and reliability, allowing for potential buffering against typical wear.

In summary, the selection of one year as the expected usage reflects an understanding of practical limits and