The integrity of quantifying "coolness." On the difference between heat shielding rate and heat shielding effectiveness.

When the season arrives where the sun feels like it's stinging your skin, you start seeing the term "heat shielding" everywhere. Just as one might compare specs for gadgets, many people want to judge the performance of a parasol using numerical values.

On the page for our "Heat Block" product, two metrics are listed: "Heat Shielding Rate" and "Heat Shielding Effectiveness Rate." At first glance, they may appear redundant, but there is a reason for this. We want to convey the "true coolness"—which cannot be measured by a single metric—more honestly and with greater clarity.

"Heat Shielding Rate": Measuring the potential of the fabric

First, the "Heat Shielding Rate" is a value based mainly on the official JIS L 1951 standard, which essentially measures the "actual capability of the fabric itself."

In this test, the fabric is stretched over a sealed space and exposed to a heat source to measure how much the temperature rise can be suppressed. This is like measuring engine horsepower on a bench test; it serves as a very fair metric for comparing the performance of a material on its own.

However, imagine actual usage scenarios. We don't hold an umbrella inside a sealed box. There is wind blowing through, heat reflecting off the ground, and space between the umbrella and our bodies. To supplement the "sensory" aspect that cannot be expressed by fabric specs alone, we need another numerical value.

"Heat Shielding Effectiveness Rate": Proving its capability as an "umbrella"

We place even more importance on the "Heat Shielding Effectiveness Rate," which is derived from the QTEC method (umbrella heat shielding evaluation test). This test uses the "umbrella" as a finished product rather than just the fabric.

What makes this test unique is that it precisely simulates actual usage environments.

• Realistic spatial design: Because the test is conducted in an open environment, the way heat escapes is also taken into account.

• Artificial sunlight: Special lights that mimic the wavelength of actual sunlight are used.

• Concept of distance: The distance from the head varies between a long umbrella and a folding umbrella when held. The measurement position is determined by replicating that "sense of distance."

In other words, the Heat Shielding Effectiveness Rate is a percentage showing "how much heat was blocked when using this umbrella compared to a state without one." It can be called a practical score that is closer to our daily lives.

Honest spec disclosure creates trust

Why go through the trouble of conducting two types of tests? Because an umbrella is a tool that requires both "numerical data" and "sensory experience."

We prove the high potential of the fabric with the "Heat Shielding Rate" and demonstrate its performance as an assembled product with the "Heat Shielding Effectiveness Rate." Only when these two perspectives are aligned can we confidently assert that "this umbrella is cool."

Knowing the background behind the spec sheet will make choosing a parasol a deeper and more satisfying process. The figures published by Amvel are not mere marketing claims. They are our promise to you, designed to protect you during extreme heat.