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Mortar Dust

It is a staple of masonry professionals. The substance that holds material together, fills and seals gaps between building blocks, and even adds to the design and style of the project. Mortar is a key element in masonry work. However, the dust generated by cutting, grinding, or chipping it brings potential health hazards if exposure levels are not controlled. In this article we will consider mortar, what it is made of, and see how workers can be negatively impacted by exposure to mortar dust.

What is Mortar?

Depending on the context and with whom you are speaking, the term mortar may have different meanings. For the purposes of our discussing though, we will be talking about mortar in the sense described by Wikipedia. That resource describes mortar as follows:

a workable paste which hardens to bind building blocks such as stones, bricks, and concrete masonry units, to fill and seal the irregular gaps between them, spread the weight of them evenly, and sometimes to add decorative colors or patterns to masonry walls.

This "workable paste" acts as a "glue" so-to-speak to hold blocks, bricks, and other units together. It is made of four ingredients mixed in varying ratios. The four ingredients are:

  • Water
  • A Binder (Usually Portland Cement)
  • Sand
  • Lime

Mortar contains ingredients that contain respirable crystalline silica. This means that mortar dust has the potential for causing ailments and health problems associated with silica.

Mortar Variations

In a number of areas, including the United States, there are five standard mortar variants. These are available as dry, pre-mixed products. The five mortar types each have a specific degree of strength according to the ratios used in the mixture of the four ingredients mentioned above. Letter designations are used to indicate the mortar type. The letter designations are as follows:

  • M
  • S
  • N
  • O
  • K

The recipes for each of the five mortar variants are shown in the following table:

Mix Ratios for Each of the Five Mortar Types
Portland Cement Lime Sand Designation Letter
1 ¼ M
1 ½ S
1 1 6 N
1 2 9 O
1 3 12 K

As mentioned previously, the strength of the mortar is related to its mix ratio. To be more specific, the higher the lime content is, the weaker the mortar will be. Therefore, the table above lists the mortar types in order from strongest to weakest.

Silica Content

As you can see in the table above, the amount of sand (a substance containing silica) increases as the lime content goes up. So, the more sand that a mortar has, the higher the silica content and the more potential there is for exposure in the mortar's dust. But what are the potential health issues that stem from mortar dust.

Potential Mortar Dust Hazards

Since mortar contains respirable crystalline silica, the dust from mortar has the potential to cause health issues associated with it. Several health problems are associated with respirable crystalline silica. Some of these include:

  • Lung Cancer
  • COPD
  • Lung Scarring
  • Silicosis
  • Kidney Disease
  • Lung Disease

Because the dust from mortar has the potential for respiratory problems, OSHA has published guidelines regarding respirable crystalline silica. Among the guidelines are methods of controlling dust exposure to professionals.

Mortar Dust Control

There is more than one way to control dust exposure in the work environment. Professionals use one or more of these methods to limit exposure to silica particles that wreak the havoc on the lungs and body.

Personal Protective Equipment

The first method for limiting exposure to mortar dust is the use of PPE. For example, wearing a respirator while performing dust-producing tasks such as tuckpointing is one way to reduce dust exposure via PPE.

Dust Collectors

Another method for controlling dust in various work environments is the use of dry dust collection systems. Even though this method of controlling dust is not practical for every task, it is an effective way to prevent dust particles containing silica from being inhaled by either workers or others in the area being worked.

Dust Extractors

The next way of controlling dust in the work environment is through the use of equipment known as dust extraction equipment. This is similar to the previous method but it involves collecting dust from a targeted work area where dust is being generated. Thus, "extracting" the dust from as close to the source as possible; preventing the area around the work from becoming dusty.

Working in Wet Environments

The last method for reducing dust while working with mortar or other silica dust generating materials is by using water. By making the material wet while working, dust is greatly reduced. Therefore, cutting, grinding, or chipping doesn't create a cloud of debris that would exist in a dry environment. However, once the water dries, the potential for the particles to be stirred up into the air does exist. So, having a way to manage the resulting particles is recommended.

In summary then, mortar dust is the result of working at removing mortar from a project consisting of stone work. Because of the components of mortar, the dust that is produced contains silica which has the potential for causing health problems if breathed by people either working on the mortar or in the area of the work. And controlling the dust by making use of one or more dust control methods contributes to a safer work space.

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