Street Sweeping Brooms: Wafer Broom

From municipal streets to construction sites, street sweepers are used every day to clean up various types of debris. Operators have a choice in what type of broom they put on their sweeper. A popular broom option for sweeper attachments and road construction sweepers, based on their compact size, easy installation, and cost-efficiency, is the wafer broom.

Wafers have made many nicknames for themselves over the years like whiskers, broom sections, or discs, just to name a few. Simply put, wafers are individual, round broom sections that stack together on a wafer rack to make a full-width broom core. If you decide to sweep with wafers brooms, there are a few things you need to know.

How A Wafer Is Measured

Wafers are available in many different sizes and are based on the make and model of the sweeper or sweeping attachment. You’ll be able to determine the size of the wafer by measuring both the inside diameter (ID) and the outside diameter (OD) of the wafer.

The ID of the wafer is based on the diameter of the wafer rack on the sweeper. Each wafer needs to be snug and slide over the rack. Here are a few standard wafer ID sizes: 6 3/8”, 7”, 8 1/4” and 10”.

Next, we need to look at the OD of the wafer. If possible, you want to take the measurements from a new wafer, as wafers wear with use, the OD will change and get smaller. Some typical wafer OD’s include: 21”, 24”, 26”, 27”, 32” and 36”.

For example, when someone asks, “What’s the size of the wafer your sweeper uses?”, you can answer with 10” x 32” or 8” x 26”, listing the ID followed by the OD.

Different Wafer Styles

There are two different styles of wafers, a flat wafer, and a convoluted wafer. These styles refer to the shape of the inside ring of the wafer, which is typically a steel ring. The ring holds the bristle together and slides over the wafer rack. The flat wafer, as you may have already guessed, has a flat ring. Alternatively, the convoluted wafer has a wavy ring, meant to create space between each wafer on the rack.

When mounting a flat wafer on a wafer rack, a spacer is placed in between each wafer to create the spacing on the broom core. The standard configuration is wafer, spacer, wafer, spacer, and so on. These wafers also have a single pin in the ring that catches the bar on the wafer rack so that the wafer rotates as the sweeper drive spins the wafer rack.

Flat wafers do not need to be stacked in any specific way on the wafer rack, although common practice is to alternate the placement of the pin while stacking the wafer. If a denser broom is needed, the spacer can be removed, and each wafer can just be stacked directly on top of one another.

The convoluted wafer, on the other hand, does not need a spacer due to the wavy design of the ring. There are two pins inside that are designed to help with the placement of each wafer on the wafer rack. The convoluted design has high and low points around the ring that need to line up correctly with one another to create the proper spacing throughout the broom core. Each wafer is rotated a quarter turn on a standard 4-bar wafer rack and a third turn on a 3-bar wafer rack. This allows the high spots on one wafer to match up the low spots of the next wafer creating the space needed to build a standard broom.

Bristle Type

A wafer can have different types of bristle. The most common of which is poly. A poly wafer has bristle made from extruded polypropylene, with different colors and weights. The poly bristle has a high level of flicking action and rigidity which is what allows the wafer to effectively sweep.

When a more aggressive sweep is needed, a wire wafer can be used along with a poly wafer. The wire wafer helps to cut through mud packed on the road and helps with sweeping heavy millings. Wire wafers are never used alone to make a complete broom because it still needs the flicking and sweeping action of the poly bristle. The wire is simply a compliment for those tough jobs where something more aggressive is needed.

When the application requires a wire wafer in your broom, you have two options. You can alternate a poly wafer and a wire wafer on your wafer rack to make up your broom core, or you can use what’s called a “combo wafer” which, you guessed it, combines poly bristle and wire in a single wafer so that you don’t have to alternate wafers or carry multiple inventors.


The length of the broom core will determine the number of wafers needed to make the broom. Most broom assemblies allow for the use of flat wafers or convoluted wafers, but the style of wafer will determine the exact amount needed. For example, an 8’ broom takes approximately 56 flat wafers with 55 spacers. The same 8’ broom will use only 47 convoluted wafers.

Wafers are typically sold by the box and depending on the size wafer, you can expect anywhere from 24 to 28 wafers in a box. Spacers are not typically included with the wafers because they’re re-usable and don’t need to be changed every time the wafers are changed. So, make sure you save your spacers!

Stay safe and happy sweeping.

Mike Santos, Sales and Marketing Manager at Keystone Plastics, Inc.

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