Visiting Singapore: A Look at Bar Grating

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.

Singapore skyline, singapore trench drain, asian trench drain, bar grating, trench drain bar grate

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

Rain in Singapore prIt 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.

shallow trench drain, open trench drain, open channel drain, bar grating catch basin, steel bar grating

I’ll begin this expose’ with the above 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!!!

steel bar grating, bar grating tile, custom trench drain, drain against wall

Tile, concrete and stone are common hardscapes you see beside trench drains. In the above 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.

steel plate grating, steel trench grating, steel bar grating, trench drain covers

The trench grating shown above 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.

flanged trench grate, bar grate with wings, grating with lip, high volume grates

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, please feel free to email me at

For inquiries on the purchase of bar grating or trench drain systems, please call the friendly folks at Trench Drain Systems on their toll free line: 866-570-2333.

Trench Drain at Arrowhead Stadium – Kansas City, Missouri

I recently had the opportunity to visit Kansas City again and review the use of trench drain at Arrowhead Stadium, home of the Kansas City Chiefs.  Earlier in the year, I visited Kaufman Stadium, the sister stadium and home of the Kansas City Royals.  At that time, we discussed slot drains and radius drains used to help evacuate surface water.  At Arrowhead Stadium, some of these same systems were used.  However, I saw greater variety of products and applications.  In addition, I was able to see some problems encountered with existing products.

football game in Kansas City

To get a good idea of the breadth of products used at the stadium, I took an opportunity to get an “inside look” and go to a football game.  The Pittsburgh Steelers were playing the Chiefs on Sunday Night Football.  The Chiefs were using a substitute QB and had some offensive issues.  The Steelers had offensive issues of their own, just coming off a bye week and being a little rusty.  Both defenses played well leading to a low scoring game with a high turn-over.  In the end, Steelers outlasted the Chiefs in the 13-9 routing of the home team.

Arrowhead Stadium has recently gone through a remodeling, adding a new press area, a founder’s plaza, and a hall of fame.   I was impressed with the changes I saw, having been an employee of the Chiefs organization some 35 years earlier.   Upon entering the stadium, I headed down to the stairs on my way to the field.  At the base of the stairs, I noted Zurn Stainless steel perforated grating used in a Z886 channel.  It was fitting that the drain was at the base of the stairs, which would be a collecting point for the rain and melting snow tracked into the stadium from the barrage of pedestrian traffic.

Perforated grating

I also want to point out that due to the high pedestrian traffic at sports venues, drain grating is most always heel-proof, or at least ADA.  That is to say, the open area which makes up the holes of the grate is less than 3/8″ in width.  Also, you will see an effort by the architect to specify a slip resistant surface on the grating.  In the case of the Zurn Grate, the perforations included some raised dimples which made a gripping action for the soles of a wet shoe.   The particular Zurn Grate style is the Z886-PSC.

Making my way to the field, I was able to inspect the field perimeter drain.  This drain runs around the field and about 10 feet from the wall stand.  This particular drain had galvanized steel perforated grating in meter lengths as is common with the European style products such as Polydrain, MEA or ACO drain.  All three of these channel systems are basically identical.  I suspect that this particular product was the PolyDrain system due to the lack of brand identification on the grating.  MEA and ACO drain tend to put identifying marks on their grates.

Strained trench drain grate

The evolution of sports broadcasting has had an effect on the trench drain of this stadium and, I suspect, other stadiums.  Originally when this drain was installed, I’m sure the designers envisioned that the loads seen by this grating would be football players, coaches, security personnel and maybe a golf cart of some sort.  Now-a-days, there is constant wheel loads from television camera mobile scaffolding going over the drain grates.  This causes the resultant bellying-out of the typically weak grating.  This is made evident in the photo above.  The groundskeeper of this field would be wise to replace these grates with an ADA cast iron grate or reinforced Perforated grating when they schedule the next maintenance on these drains.

Lamar Hunt in Kansas City

The Founder’s plaza is a grand court at the business entrance and ticket booth at Arrowhead Stadium.  Here, they have a fountain, an ornate hardscape, and memorial paver stone courtyard which requires quite a bit of drainage.   Earlier in the year, I was called by an engineer from a local contracting company, George Shaw Construction, to discuss the replacement of grates that were failing at the Founder’s Plaza.  At the time, the engineer was considering a stone based, reinforced polymer concrete grating called Jonite.  This product proved to be too costly for the Chiefs organization, who decided to live with the broken grates – at least for the time being.

Upon arrival to the Founder’s Plaza, I quickly located the problem trench grating (See below).  I had seen this product earlier in the year in the general admission section of the adjoining baseball stadium, Kaufman Stadium.  When I first viewed this grate, I suspected it was custom because I saw no markings.  But here at Arrowhead Stadium, I was able to pick the grate up and view it in detail.  The grate was an 8″ wide by 24” long galvanized cast iron product made by a boutique foundry out of California named Ironsmith.   The grating pattern, Olympian (9045-8), is meant for pedestrian loads only.

After examination of a broken grate, it was clear to see the root of the failure.  The recess of the trench which held the grate was designed to be one inch deep.  The Ironsmith grate showed a one inch thickness, required to bring the grate flush with the adjacent hardscape.  The grating design incorporated 1/4″ thick corner and edge pads (sometimes called pedestals) which are used to stabilize the grate within the track and prevent rocking.  The actual rail body of the grate was only 3/4 inch thick.  The grate cross bars, attached to the edge rails, are around 3/8” thick.  The pedestals are intended to be ground, if needed, to help facilitate stability.  In this case, however, the pedestals acted as suspension points along the weakest axis of the grate.  At first glance, one would think the strength of the grate would be a function of the multiple 1 inch thick cast iron support member spanning the 8″ dimension.  In fact, the Ironsmith Olympian design is only as strong as the two 3/4″ edge rails that spans 12 inches between any two adjacent pedestals.  This is a weak grate design and can be easily fail under light loads.  No wonder so many of these grates were found broken.

Ironsmith Galvanized Cast Iron

Elsewhere in this same plaza, other types of trench drains were used.  Around the fountain, designers used a trench drain with a slot drain extension rather than a standard grate.  These drain sections were 40 inches in length (one meter), typical of European style products such as MEA and ACO drain.  Both of these manufacturers have a galvanized steel slot extension which is used in place of a grate.  This allows the water to be drained into a 3/8” wide continuous slot that is well hidden from view.   The slots are ADA compliant, as well, but watch out for cigarette butts clogging the slots!!!  They only drain as well as they are cleaned.

Slot Drain

One last example of trench drainage is along a sidewalk curb.  This particular product is manufactured by ACO drain as shown by the brand mark.  The grate, Type 494, is plastic and ADA compliant.  It is resting in their K100S channel which is made of polymer concrete and utilizing a galvanized steel edging.  This pre-sloped system is made in the European tradition and is pretty much identical to MEA’s Z1000 channel.

ACO in Kansas City

Arrowhead stadium displayed a nice assortment of trench drain products.  At this venue, the exposed grating was heel-proof and ADA compliant due to the high volume of pedestrian traffic.  Product manufacturers included Zurn, ACO, Ironsmith and possibly Polydrain.  I was able to view design flaws of a product made by Ironsmith and see some significant deformation of grating that was under-rated for the application.

If you would like to discuss any of the above products, contact us at Trench Drain Systems (TDS).  We specialize in all aspects of trench drains, channel drains and trench grating products.  Call us toll-free 866-570-2333 to speak to one of our sales specialists.  Or, visit our website

Large Residential Catch Basin Options

If you discuss catch basins with an excavating contractor, they immediately think about large pre-cast concrete storm water drainage structures that are part of municipal, state or federal drainage systems. These basins commonly have an interior dimension of 2’ x 4’ or larger and are made of 8” thick reinforced concrete.

A landscape contractor’s perspective on catch basins will be different. Typically, the largest catch basin used in a landscaping drainage system is 2’ x 2’. Precast concrete basins are available in this size, but they are referred to as 2’ x 2’ yard basins.

There are a number of options available for landscape contractors and homeowners who need a large catch basin. By large, I am referring to a basin with a maximum size of 2’ x 2’. A catch basin of this size (2’ x 2’) is at the boundary that separates commercial products from residential products. Basins larger than 2’ x 2’ are generally made with the intention of being exposed to heavy traffic. This article will be discussing some of the “large” catch basin products available for residential application.

Pre-Cast Concrete Catch Basin

The first product to discuss is the traditional pre-cast concrete yard basin. These products are made in a concrete shape factory using a metal form. The wall will generally contain some amount of mesh reinforcing. There may be indentations in the walls (known as knock-outs) that will make it easy for a contractor to remove a section of the wall and install a drainage pipe. Usually, the largest pipe that can fit into this basin is a 15” diameter concrete pipe. These basins can be made with pre-existing drainage pipe holes to your specification. Grating options are traditionally limited to heavy duty cast iron slotted or bar grating. Though this type of basin is relatively inexpensive, they require a backhoe or small crane to set them into place. Your local pre-cast concrete company may have these in stock, but you will need some serious construction equipment to move and place it.

Cast-in-Place Concrete Catch Basin

If a pre-cast concrete catch basin is too heavy for you to handle by yourself, consider forming a large basin in place. Catch basin forming systems exist that allow you to build a concrete catch basin at your location. After digging a pit for the catch basin, set a metal frame and Styrofoam form inside the hole and suspend it with rebar above the base of the pit. The form will become the “reservoir” of the basin that collects all the water. The space around the form will become the concrete walls of the basin.

Prior to pouring concrete around the form, attach any drain pipe (entering or leaving) by simply butting it up to the form and securing it in some fashion.Once you have the form secured in place with all the desired plumbing, pour concrete around the form.

Depending on the size of the basin, you may choose to hire a ready mix concrete company to bring in “the mud”. However, if you excavated your hole with tight dimensional control you may feel comfortable hand mixing bagged concrete and saving yourself a little money.

I mention this because most ready mix concrete companies have a minimum delivery charge. If you are making a 2’ x 2’ x 2’ catch basin with a 6” thick wall, you will need a half yard of concrete (or 2000 lbs.). I’d probably get a concrete truck and pay the minimum charge. However, if I was going to make the walls of that same catch basin 3” thick, I might decide to hand mix the concrete.

Visit our Trench Drain Installation page to learn more about installation methods.

Polymer Concrete Catch Basins

Another option for large yard basins is the polymer concrete catch basin. Polymer concrete is composed of natural mineral aggregates and a polymer binder. It has a very high strength in comparison to conventional concrete. This high strength allows very thin walled and light weight structures to be made with comparable properties as pre-cast concrete would have.

Product lines, such as Polycast, include 24” x 24” x 24” boxes that are use to build a catch basin. For additional depth, two foot deep extensions can be placed on top of the solid bottom basin. Smaller catch basins made with polymer concrete are available as well.

Attaching PVC piping to polymer concrete catch basins can be a little trickier especially since it is ideal to avoid using concrete when installing this catch basin. However, you may find it is necessary to use concrete to help seal the pipe in the basin wall or maybe when forming a small apron around the grating to help direct water into the basin.

And speaking of grating, polymer concrete catch basins may have some good residential grating options, but they tend to look industrial.

Plastic Catch Basins

The final basin type I am going to discuss is the plastic catch basin. There are a number of manufacturers in the marketplace that promote plastic catch basins. I’m most familiar with products by National Diversified Sales (NDS). These products range in size from 24” x 24” to
9” x 9”. The larger NDS basins are made from high density polyethylene (HDPE) while the smaller basins are made from PVC.

Extensions are available for adjusting the depth of the basin. Piping is connected to the basin with an adapter fitting and PVC glue can be used to secure the pipe and fitting, though it is not necessary.

Catch basin grating options become better as you decrease the drain’s size. For instance, the large 24” x 24” NDS catch basin has 5 grate options. On the other hand, NDS’ 12” x 12” basin has 15 options. Plastic grates in a variety of colors are common throughout the NDS basin product line. They also have cast iron and galvanized steel bar grating. Other manufacturers also have grating options for the NDS basins. Iron Age Designs is one such company. Below are four decorative cast iron grates made for the NDS 12” x 12” catch basin. Some of these patterns are also available in sizes that fit other NDS basins.

As you can see from the examples I gave above, there are many options in large residential catch basins. I realize that the information given here may not answer all of your questions. To get more details on a product or advice on a catch basin application, send me an email at or call Trench Drain Systems at 610-638-1221.