Hinged drainage grating is cool!!! I think we need to use more of it in the United States. A few US companies offer hinged cast iron grates, but, I’ve never seen hinged bar grating used in the United States.
The ability to open a drain for cleaning (which this drain needs) is essential. If drain grates are locked into place with a locking mechanism or if the grates are the bolt-down style, opening the drain becomes more problematic. But when the drain grates aren’t attached in some way, unscrupulous or financially desperate people could take the grates and trade them at the scrap yard. Hinged grating solves both of these problems. Grating can be removed for easy cleaning access while the still being attached.
Below is another hinged grating which uses the wide section of the bar stock as the walking surface. By placing the bars in this manner and minimizing the open space between them (1/4” or so), the designers of this grating have made a heel-proof and vandal proof trench cover. This hinged, flat bar style will be able to support heavy loads across spall spans. However, if the span of such a drain would increase too much, the bars would begin to deform under the weight of pedestrian loads.
Note that the hinged grating above is galvanized. Galvanization has two purposes in this situation. First, galvanization helps protect the underlying steel from oxidation or rusting. Singapore, being an island, is surrounded by salt water. Just the proximity of the ocean to a moist, humid atmosphere creates a corrosive environment. This, by itself is a reason to galvanize steel grating. A second, though minor, reason to galvanize is for slip resistance. Galvanizing imparts a coating on steel that is offers a degree of natural slip resistance, especially after initial oxidation. Chances for slips and falls are reduced by having that little extra abrasiveness on the drain cover.
Stainless Steel Grating
Another common trench grating material that has good resistance to corrosion is stainless steel. I found a good assortment of stainless steel bar grating throughout Singapore. All were in public places near subway stations and tourist sites. Again, all the trench drains that used the stainless steel grating were formed in place to accommodate the adjacent stone laid walking surface.
The photo shown below is my favorite Singapore bar grating. This is a simple welded stainless steel grating made of 3/8” square stock. The support bars are made of 3/8” square stock, as well. The spacing of the bars leaves an opening of ½”. The grating is resting between stone pavers and handicap pavers on a cast in place trench. The location is a sidewalk within a large park called “Garden by the Bay”. It’s a nice product in a world class park.
Another example of heel-proof bar grating was found at an entrance of an elevator leading to the observation deck of the Sands Marina Bay Hotel. (See below.) This was an amazing hotel with a spectacular view of the city and the bay. Consider staying here if you travel to Singapore.
The grating was made with 1 inch wide stainless steel bar stock with the wide edge exposed to foot traffic. You can see the steel supports beneath the flat bars at about 4 inch intervals. This is needed because of the lack of rigidity the bars have when laid in this orientation. Each grating did have a 1/8th inch trim band surrounding the entire grate which helped to make it stiff.
An alternate to making heel-proof bar grating in the fashion, is to set the steel bars on edge. The photo below shows 1/8th inch thick bars set on edge with 1/8th inch openings.
Again, supports are beneath the bar assemblage at 4 inch spacing. The bars on edge make a stronger, more rugged grating that is both elegant and functional. With 50 percent open area, this grating will be able to handle the daily rains of Singapore. This particular stainless steel cover is at an elevated train station at the resort island of Sentosa. It is a grating style commonly used in bank and store vestibules.
Slotted Drain Covers
The final two drain covers to be discussed are the slotted drain cover. These are new to me. In fact, I don’t recall seeing this type of cover in the United States. They must be used elsewhere in the world, though. These slotted drain covers are solid trench covers which sit in the opening of a trench drain as a grate normally would. However, to accommodate drainage, they have a single slot in the center of the cover running parallel to the trench. In these cases, they are unique because they also are designed to accept inlays stone or tile to match the surrounding walking surface.
The first cover, shown below, was part of the hardscape around Universal Studios on the island of Sentosa. The covers are approximately 12” x 12” with the center 1/3 of the cover devoted to drainage. The steel bars of the grating and the inlay frame are galvanized to help prevent oxidation. The remaining two outer thirds of the cover are used to hold inlaid stone and epoxy mortar that match the surrounding walkway. The trench drain channel seems to be formed in place and has a neutral slope. (Note the standing water when you look through the grate.) The cover is attractive, ADA compliant, heel-proof and is able to handle the high rainfall of Singapore.
The second cover, shown below, sits at the base of a stairway in the subways below downtown Singapore (Also, an awesome subway network.) Though similar in design as the Universal Studio slotted cover, these covers were made with stainless steel and sported only a single slot. An epoxy bonded concrete was used as inlay around the slot. Each cover was about 12” wide and a meter in length. As this was in a low water flow area, only a single slot was required. Still, the cover spanned a large trench, which leads me to believe that the trench could also be used for conduit or piping, as well.
What an interesting study of bar grating!!! I did not find much variety of steel bar stock in the grating products found in Singapore, but what contractors did with the bar stock was incredible. In the U.S., we have many styles of steel and aluminum bar stock used to make grating. Serrated, I-Bar, rectangular and riveted bars become part of the vocabulary when technically discussing bar grating here in the States.
Only rectangular steel bars were used to make the grating reported in Singapore. Stay tuned for Part 2 of this report, which will show more product variety as we cover cast metal and stone based grating observations.\
If you have any questions about the blog or the types of drains I’ve talked about today, leave a comment or email me at Michael@trenchdrain.biz. For purchase inquiries, please call a Trench Drain Systems specialist on their toll-free line: 866-570-2333.
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