The climate is always warm and wet in Singapore, a small island nation in Southeast Asia with a bustling economy and a diverse and growing population.
Geographically, Singapore is located 3 degrees north of the equator at the intersection of some pretty old trading routes. Singapore receives over 90 inches of rainfall a year. (Compare that with cities like Philadelphia or Cincinnati who get about 40 inches of rain per year!!) With 5.2 million residents and another 4-5 million visitors staying on a land space just over 750 square kilometers, it is easy to see why Singapore is constantly updating its infrastructure. And, of course, that infrastructure includes trench drain.
I visited Singapore in February 2013 (just in time for the lunar new year) to visit a supplier and see first-hand how the country handles the massive rainfall. Singapore takes cleanliness pretty serious. Spitting and chewing gum is prohibited. And littering? Don’t even think about it.
After winning independence from Malaysia in the early 1960s, Singapore began a campaign to clean up the country. In 1967, a major undertaking began to clean up the water and banks of the river and harbor areas. With each torrential downpour, it was easy to see that this “house cleaning” needed to extend inland toward the major generators of run-off water pollution. Over the next 40 years the government of Singapore put laws and policies in place that helped clean up the country, and they aim to keep it that way.
I came away with a better appreciation of the challenges human civilization will face as world populations grow and water management issues become more critical.
Where there is Rain, there is Drain
It is easy to see why trench drain is so widespread in Singapore’s wet climate. With the rainfall, every hardscape surface has some sort of drain. Large surfaces, which generate large volumes of run-off water, have deep trench drains with industrial looking bar grating. Parks and tourist areas tend to have ornamental grating. The trench drains inside subway entrances tend to be narrower due to reduced flow requirements and made of stainless steel.
The trench drain channels I saw all seemed to be formed on-site as opposed to Europe and the United States where modular systems tend to be the norm. This may be due to the sheer size of the drains required to handle all the rainfall. Even in the U.S., contractors tend to use formed-in-place rather than modular trench drain systems when high volume drains are required. Still, the lack of small modular trench drain systems seem to suggest that the cost of labor is still low compared to western societies.
Bar Grating – The Dominant Drain Cover
By far, the most common grating in Singapore is steel bar grating. Often, the steel is galvanized to help protect it from oxidation. Other times, it is made with stainless steel, though I did find one instance where the bar grating was made of bronze to match the surrounding aesthetic.
Bar grating designs seem to vary depending on the need for safety, ease of maintenance or aesthetics. In other cases, I found bar grating designed to help facilitated ease of manufacturing or installation in the field. In the photos below, I’ve compiled a few examples of bar grating common to the Singapore cityscape.
I’ll begin this expose’ with the left-hand photo, which shows something I’ve seen in a number of other countries, but never in the U.S. The 1 inch deep trench above empties into a catch basin with a steel bar grating top. This drain is located in a hardscape just behind a busy bus stop. In the U.S., we don’t see this type of drain because its 1 inch ledge presents a tripping hazard and, therefore, a potential lawsuit. The open bar grating is also dangerous to a woman’s high heels, another possible lawsuit.
Open grating and potential tripping hazards are fairly common in this modern city. What does this say about the differences of our two countries? Are the people of Singapore more clever or less litigious than their counterparts in the U.S.? There could be some truth to that. I do think this drain example gives us an indication of where each of our countries draws the line between personal responsibility and public safety. No matter, I risked my life taking these photos!!!
Tile, concrete and stone are common hardscapes you see beside trench drains. In the right-hand side case, a granite sidewalk is separated from a concrete step by an uncoated bar grate. The grate rests on a piece of steel angle attached to the concrete to form a lip. The grating itself is about 6 inches wide, 1 inch thick and 20 inches (1/2 meter) in length. The 3/16” bars are spaced on 1 inch centers. Uncoated bar grating of this size was a common sight in Singapore, but larger bar grating was also easy to find.
Below the grating you are able to look into the channel. The drain channel contains a little bit of debris from leaves and water. This is a good place to mention that neutral sloped channels are the norm in Singapore, but standing water indicates that water flows from the channel when there is enough head pressure.
While visiting Singapore, an article came out in the local newspaper stating that Singapore was the sixth (6th) most expensive city to live in the world. I thought New York City would be on the list but, after thinking about it, I can’t remember spending more than $15 for a draft beer. If I recall, the cost for a single can of cheap beer at a Singapore grocery store was $3.50. I bring up this point to remind everyone that Singapore is an island. They import everything into the country because they have little manufacturing, which makes prices high and skilled labor scarce. Now, let’s look at the photo below.
The trench grating shown left is ¼”steel plate with drainage slots cut into it at 1.25” spacing. This isn’t a particularly strong grate. It sits over a trench channel that doesn’t see too much pedestrian traffic. Again, standing water can be seen in the channel body below. It was probably a response to someone needing an inexpensive drain top. And, this grate was made without the use of any welded metal. In support of my previous comments, this drain cover is an example of problem solved in the face of scarce resources.
There’s More than One Way to Design a Bar Grate
Most times, drain channels are designed with a slightly wider, stepped opening at the channel top that allows the grating to be recessed within channel and the grating to be flush with the surrounding drainage surface. This design requires that the builder to know the dimensions of the grates he is to use in advance so he can form the grating recess accurately.
Another trench design eliminates the need for a top grating recess but requires more attention be placed on the grating design. The channel walls are straight all the way up to the top. So, to suspend the grate over the channel, a set of wings (or ears, whatever) has to be part of the design. The photo above demonstrates this feature. These wing supports are made using angle iron as the grating trim band. Bars are welded between the angle pieces. In the case above, it seems that additional bar stock was added to the angle edge because someone didn’t have the proper angle size during manufacturing.
A couple problems exist with this grating design, though. The supporting edges of the angle iron edges form a little lip that acts as a barrier to water and can possibly be a tripping hazard. If you get enough rain, I suppose, the water will eventually rise above the ¼” obstruction and enter the drain. But you’ll still have a certain amount of residual water to be drained.
Are you interested in bar grating? Want to know more about trench drains designed for heavy rainfall? If you have questions or comments on this article, send us an email or leave a comment below!
For inquiries on the purchase of bar grating or trench drain systems, please call the friendly folks at Trench Drain Systems at 610-638-1221.