Roof Shade is Thermal Insulation Screens for Roofs that Protect Workers from Heat While Saving Energy.

Date of interview	July 21, 2022
Interviewee (honorifics omitted)	Hiroshi Ishikawa Representative Director Ishikawa Tent Co., Ltd.

Ishikawa Tent started its business operation in Shikokuchuo, Ehime in 1950 and was later incorporated in 1989. The company’s main operation initially involved installation of rain covers and sunshades on the eaves of shops and other establishments applying tent technology. While the area has always had a large number of paper mills and paper processing factories since those days, we have been seeing an increased demand for insect-repellent and dust-proof products that are made of curtain materials in recent years. Along with the general trend for companies to improve the work environment for their employees, we saw the market needs rising for products that could alleviate summer heat and conserve energy as climate change had come to the forefront of global attention more recently, which served as the impetus for Ishikawa Tent to develop the Roof Shade − thermal insulation screens for roofs. The Roof Shade has become the company’s flagship product, which has been sold to a number of factories, warehouses, and shops.

As Ishikawa Tent used to operate an udon noodle restaurant, we knew firsthand how a shop like ours would use an exorbitant amount of electricity during summer, so we became quite interested in improving our energy efficiency, which led to the creation of the product. But even before that, we constantly heard from customers that operated their businesses out of prefabricated buildings that they wanted us to install tents on their roofs because they knew it would have a significant cooling effect. So we started thinking about a way to create shade over roofs that would be easier than pitching a tent, which was yet another angle from which the product would take shape. We initially tested this idea of laying down sudare − traditional Japanese screens − on top of roofs, which alone made a notable difference and gave us confidence about the efficacy of our approach. However, as sudare could be blown off by wind and would become frazzled and had to be replaced every year, we contemplated on a sturdier design. We then came up with this idea of implementing long and narrow screens that would allow the wind to pass through.

As the summer temperatures have been sharply rising in recent years, restaurants, convenience stores, warehouses, and factories are now faced with the issue of their room temperatures having become exceedingly high. Indeed, a number of cases have been reported, where factory workers would suffer hyperthermia while precious consigned cargo kept at warehouses would deteriorate due to heat, for which the business operators could be liable. Although the use of air-conditioning is one way of addressing this issue by forced cooling of the air, it would certainly add to the already inflationary electricity costs, so each business operator is under pressure to conserve energy through some creative means.

Unique features of the Roof Shade insulation screens

Each unit of the Roof Shade is comprised of two components, which are narrow white mesh sheets − called the roof screens − and the shade grippers whose function is to crimp the roof screens. The Roof Shade is a thermal insulation device exclusively designed for metal folded-plate roofs that are commonly used at factories, warehouses, and other large buildings.

Folded-plate roofs that are made of steel tend to heat up during summertime. While it has been reported that their temperature could get up to roughly 80℃ on the hottest day, such high heat atop a building would certainly cause the indoor temperature to rise, resulting in decreased air-conditioning efficiency and possibly harming the health of the workers inside the building.

In terms of its installation method, the Roof Shade can be set up simply by first covering a folded-plate roof with the roof screens and then crimping them with the shade grippers so that they are fastened to the roof. Once these narrow screens are fastened to the roof in zigzag formation, the roof surface is completely shielded from sunlight when it is viewed from above, while there are triangular spaces in between when viewed from the side. These spaces are designed to keep the roof well-ventilated and prevent the heat from getting caught inside.

We also measured temperatures at our own factory building and discovered that the difference in surface temperature between the areas that were exposed to the sun and the shaded areas was 26℃ at most. So if we could reduce the surface temperature by 26℃, the room temperature could preferably be brought down by 4℃ to 5℃, which would be helpful in improving work efficiency and preventing cargo deterioration inside the warehouse.

We also receive many inquiries from customers about how sturdy the Roof Shade is, who are mostly concerned about how the product would be able to endure typhoons, snow accumulation, and torrential downpours. The Roof Shade indeed has demonstrated its sturdiness through the most demanding of weather conditions, including Typhoon Jebi that ravaged the Kansai and Shikoku regions in 2018 as well as the frigid winter of 2020 in Nagaoka, Niigata that recorded snow accumulation of 1.4 m. When a torrential downpour hits the roof of a building that is made of steel panels, it creates such a loud sound that prevents people from having normal conversation while performing administrative tasks. The Roof Shade can not only dampen the sound of the rain but also protect the roof surface by covering it with screens.

Due to the rising costs of gas, crude oil, and electricity of late, our company has been receiving more and more inquiries about the Roof Shade, and we feel the product has been garnering much attention at exhibitions. The Roof Shade is basically maintenance-free until the end of each specified replacement period, and even if it suddenly gets ripped, etc., it could be mended, so that is why our customers apparently feel the product is easy to implement. In addition, as many companies use leased warehouses, shops, etc. to operate their businesses, when it is time for them to vacate those pieces of property, they are contractually obliged to restore them to the original condition. So this is another advantage that the Roof Shade provides, because the simple removal of those screens from a roof can restore the roof to its original condition, unlike paint application or physical roof alteration, etc.

Difference from thermal insulation coatings

Of all types of thermal insulation coatings, the most generally used one is highly reflective coatings. However, as the surface of such coating becomes increasingly smudged over the course of several years, the highly reflective property of the coating is diminished. Meanwhile, the Roof Shade can continuously perform the same effective function as long as the shades blocking the sun are not lost, even if their surface may get smudged.

There is another thermal insulation method involving double-folded plates, where there are double roofs between which thermal insulation material is installed. This engineering technique involves use of heavier materials, which could be an issue, as certain buildings are not designed to support their weights. Because the Roof Shade only weighs 1.2 kg per square meter, it does not place any significant load on the buildings where it is installed.

In addition, as the aforementioned double-folded plate design is a kind of thermal insulation technique, it comes with the disadvantage of heat storage in the insulation material between the roofs. While this slows the heat conduction from the external environment, the heat that gets stored will be kept within even from the early to late evening when the temperature becomes cooler. Furthermore, if there is a heat source in the building, the heat insulation will keep the additional heat within, which will cause the room temperature to rise. Therefore, it is important for the users to know the difference between thermal insulation in terms of heat conduction and thermal radiation and apply the technology accordingly.

As I have explained earlier, the Roof Shade only has two components, one of which is the roof screens and the other being the shade grippers. Installation of the product is quite simple, which only involves laying each screen over a folded-plate roof and crimping its seams with the grippers to fasten it to the surface. So, unlike the installation of double-folded plates, it does not require large heavy equipment or scaffolding and can be implemented at a significantly reduced cost. This process of installing each screen is repeated at 1-m intervals across the roof, and a single worker can finish installing screens over an area of 150 m² in just one day. So, for example, the Roof Shade can be installed on the roof of a factory rather quickly on its non-operation day, which is another key advantage of the product.

Future outlook

While the Roof Shade is currently available only in the color white, we have been investigating the possibility that different color combinations on the front and back of the screens would increase the product’s thermal insulation performance, we sprayed the back with a black paint and conducted comparative temperature measurements, which revealed that the one with the back painted black had improved radiation heat insulation by about 3C. So we are planning on testing out different color combinations to continuously improve the product’s efficacy. In addition, while the current model has a usable product lifespan of 10 to 15 years, we will work on improving its durability and longevity while recognizing that the Roof Shade is among the class of construction materials that should last to the extent possible.

The Roof Shade has been mainly used by customers in the Seto Inland and Tokai regions along the Pacific coast as well as in the Kyushu region. However, since it can withstand the weather in other regions where there is snowfall, we will be actively promoting the product along the coastal regions facing the Sea of Japan, etc. where snow poses concerns. As those snowy regions consume significant amounts of energy during wintertime, this product could be implemented there such that snow accumulates over the roofs creating snow-formed spaces serving as a sort of thermal insulator shielding from the cold. In addition, we believe the product might be useful in the hot countries across South East Asia, etc. throughout the year, so we will be promoting the Roof Shade overseas in the future.

While our company was initially focused on providing insect-repellent and dust-proof solutions using curtain materials for work environment optimization, the development of the Roof Shade has allowed us to help address the issues of global warming and energy conservation, which is a major motivational factor for us. So we will be promoting the Roof Shade not only in Japan but also all over the world. We are committed to helping workers being exposed to high heat improve their work environment while saving energy to the best of our ability.