In construction industry every project involves nearly some form of cutting concrete or core boring. Hand-held saws are used in the construction project to cut or shape paving slabs, stones or other concrete products.

Cutting concrete may seem to be simple but on practical ground there are several safety measures to keep in mind to have a safe and successful concrete cutting or boring project.

Safety and concern becomes an issue with concrete cutting because the concrete dust generated by the cutting action contains high respirable crystalline silica content. Breathing in this dust can lead to the development of respiratory ill health affecting your lung tissue resulting in serious breathing difficulties depending on the extent of exposure

Therefore, dust control becomes an important consideration when cutting concrete either with a saw or a drill or core boring bit.

The two most dust Control methods are:

1. 1. Wet Cutting System:

In wet cutting the dust is collected in the cooling water and pneumatic devices that pulls the dust away in an air stream. Wet systems are preferably used on saws powered by combustion engines or compressed air. Wet dust suppression should not be used on saws that are electrically operated.

Wet cutting systems spray water onto the rotating cutting disk to reduce dust emissions. There are two sources by which water may be supplied.

(a) Portable Pressurised Tank System
This pressurized tank system consists of a polypropylene bottle containing approximately eight litres of water. The bottle is connected by narrow plastic tubing to two spray heads or jets normally attached to opposite sides of the guard. An on-off valve is fitted to control the water supply. An in-line filter is often fitted to prevent the heads becoming blocked. The spray heads/jets can be made from polypropylene but brass is considered a more resilient material. Water flow is produced by pressurizing the tank by hand.

(b) Mains Water System
This system is essentially the same as the tank, except the water source is from mains supply through a hose to the two water jets. Studies have shown that a minimum flow rate of about 0.5 litres per minute is required to optimise dust suppression. Low flow rates  will reduce performance. Very much higher flow rates do not improve dust suppression, they only increase the need to refill the portable tank more often.

Difference between Portable and Main Water System

The portable tank needs to be regularly pressurised to maintain the flow rate.

The mains water system does not have this limitation but portability is restricted by the need to cut near a mains supply. The portable tank is more flexible as it can be easily transported around the site but it still requires a water source for refill.

For cutting a paving slab with a diamond tip blade normally requires a single pressurization stroke with portable system whereas tank sytem require re-pressurising during the cut if adequate control is to be maintained.

Precautions:

Diamond cutting blade or other abrasive disk cutting device such as concrete saw, uses water to  lubricate and cool the cutting tools. The spillage of cooling water on to the surface during  cutting should be managed by providing a  drainage or a vacuum system like a wet vacuum which can be used to control the spillage of cooling water.

When using electric powered tools, adequate grounding, insulation and appropriate ground fault protection must be provided. If proper safety measures are not taken by the operator while operating electric toll and standing in a puddle of water can be fatal .

Core drilling machine requires an additional precaution as most of the machines depend on suction to keep the base in place during the drilling operation. The friction of the base suctioned against the floor provides the resistance to rotation while drilling depending on wether the floor is slicker or rough. The rough floor may provide more friction and will not allow a strong vacuum seal against the floor. In either case the vacuum seal is not completely reliable and may fail during the drilling operation. The operator must be aware about this and should keep his body out of the possible rotation path of the machine base during   core drilling operation.

A reliable and secure method to work with core drilling  machine is to have a concrete anchor through the base in addition to the vacuum seal. Most machines have a provision for such an anchor and the small hole required for the anchor is easily repaired in the concrete floor.

What lies beneath the concrete should be an important consideration even for a straight line cut with a concrete saw or making a round hole with a core drill. Concrete imaging and scanning is the technique used for relocating the presence of rebar,pipes, conduits, steel wire mesh,sinkholes, plumbing holes or even electrical conduits often buried in or under the concrete.

Concrete cutting equipments require sharp tools, a good supply of cooling water and a skilled operator to handle these machines. Operating concrete cutting equipment can be simple and safe, but the operator must be familiar with the potential hazards and should be well skilled in his concrete cutting profession.

1. 2. Local Exhaust Ventilation:

The method of local exhaust ventilation used on hand held concrete cutting saws uses the saw’s guard as a type of high velocity hood. The guard is connected to an industrial vacuum cleaner which provides sufficient exhaust ventilation to capture the majority of dust emitted during the cutting operation. Guards with adjustable inner sleeves are preferable. These maximize enclosure and can be adjusted to accommodate different depths of cut. This system does not produce the wet slurry associated with wet dust suppression.

Common Problems and Solutions with Control Systems:

(a)Wet Systems
• Chalk is used to mark the line of cut which can easily wash off by water supply generated in wet system. Wax crayons or a carbon brush (from old electric motors) are better options to be used instead of chalk.
• Operators require waterproof PPE as both pressurized portable system and mains water system make use of water.

(b)Local Exhaust Ventilation
• Abrasive wheels wear during cutting activities. A system with an adjustable inner sleeve does not automatically compensate for abrasive wheel wear. Diamond wheels wear less quickly and are recommended for this system.
• A generator is required for both vacuum cleaner and saw. Small portable generators can be moved around the site on a wheel barrow.
• Operators should be aware of correct posture as local exhaust uses 9 inch diameter wheels which require operators to bend a little lower during cutting operation.

Personal Protective Equipment
• Concrete cutting operator should be provided with suitable RPE as concrete cutting products contain high silica.
• Dust mask is required while emptying the vacuum cleaner.

Core drilling is a vastly used technique that is followed in recent days in various construction and geo-technical works. Moving far ahead from the convention manual drilling methods, advanced core drilling has come up with all its cost effective strategies and secured mode of operations. With the tremendous improvement in constructional methods and equipments, core drilling has found a great scope of expansion and development. Since the people who are directly involved in diamond core drilling and cutting workhouses, it is essential to ensure the security and safety of the employees engaged in core drilling area. The latest electronics equipments are used now days to ensure high performance in least time period with minimal risk factor. Core drilling tool and techniques are used particularly in inserting pipes, making holes for manholes, deep penetration works and exploration activities.

There are several technical break-through that took place in the field of core drilling and diamond core drilling industries. The cites that engage workers for core drilling and cutting jobs, ensure their security arrangements in the first place. This work requires highly skilled professionals who have a clear-cut idea about the task of core drilling. The equipments such as drill motor, gearbox, drill jig and electronics core drilling machines need experienced and skillful hands to operate. So, the core drilling contractors give it special attention to train them properly prior to including them in live projects. When we talk about a core drilling contractor, MD, the workers involved in the job are given training and they are provided with legal license to work in places like deep boring, mining and excavation works. There are several diamond core drilling contractors of Maryland, Virginia, Frederick, York, Newport, Pennsylvania and Manassas who are very much strict in following Health and Safety Management Plan provided by the legal authorities of State.

Gone are the days of manual core drilling machines. Now, there is large number of fully automated core drilling machines available in the market. These are both cost effective and also highly secured. A well-known core drilling contractor MD always makes it sure to implement latest core drilling machines like HXY—2BT Core Drill, drilling rig, electronic motors and many other equipments to make the work faster and smoother. The firms that operates with the projects of core drilling, thread cutting, countersinking, twist drilling and reaming make use of latest tools and machineries for major construction works like bridge building, dam construction, Harbor construction and many other.

There are many core drilling contractors in MD and diamond core drilling contractor MD who are popular in their local region for providing quality works in drilling and cutting projects.

Diamond core drilling is the work of experienced professionals. Those who are involved in diamond core drilling operation are given proper guidance and training before they undertake some live operation. It is the task of skill and strength for the experienced workers in Diamond Core Drilling firms. There are many  core drilling companies that are properly licensed for using employees in this risky project. Often, it is noted that there are serious accidents in the work area of diamond core drilling site and also in concrete cutting operations. To avoid all this, Safety management plan is implemented to minimize the chance of any kind of mishaps.

In a standard diamond core drilling company, employees are provided rigorous training so that they can get the idea of the work in actual sense. Also, it is essential for the diamond core drilling company to provide health and safety insurance to its employees. This is done so that the employees feel it safe and comfortable to work in this kind of environment. It is the prime responsibility of the company management to take care of all its employees and ensure their health and happiness.

Some of the important points that are required to follow are given below:

• We provide all our employees a safety manual and it is mandatory for each and every employee to go through it in order to have a detailed idea about all types of core drilling equipments.
• Drilling operators are strictly suggested to wear protective equipments as recommended by local, state or federal standards.
• The diamond core drilling machine operators should wear safety equipments like safety goggles, safety footwear, snug fitting clothes, hearing protection, head protection, and proper respiratory equipment. Employees who are working as diamond and concrete cutting operations should not wear loose-fitting clothes and jewelry while operating.
• Employees should check the functionality of the drilling equipments and the electrical devices that are required for diamond core drilling and concrete cutting. Hydraulic drills and their functionality should be checked before operating for core drilling. In case of any type of disturbances, particularly in the electrical devices, they should be switched off and plug connection should be broken immediately. Also, it is suggested not to try in repairing the equipment unless the employee has a thorough knowledge over it.