Below are potential conditions that can lead to personal injury and property damage. Employers with hose assemblies in fluid systems are encouraged to provide training, including the information in this article, for maintenance personnel and other employees working with and around hoses under pressure.
Media permeation: Hoses should always be used in well-ventilated areas. Certain media will permeate through hoses that can displace breathable air in confined spaces.
Fluid injections: Fine streams of pressurized fluid can penetrate skin and enter a human body. Fluid injection wounds may cause severe tissue damage and loss of limbs. Consider the use of guards and shields to reduce the risk of fluid injections.
If a fluid injection occurs, contact a doctor or medical facility at once. Do not delay or treat as a simple cut. Fluid injections are serious injuries, and prompt medical treatment is essential. Be sure the doctor knows how to treat this type of injury.
Avoid all contact with escaping fluids. Treat all leaks as though they are pressurized and hot or caustic enough to burn skin.
Whipping hose: If a pressurized hose or hose fitting comes apart, the loose hose end can flail or whip with great force, and fittings can be thrown off at high speed. This is particularly true in compressible gas or fluid systems. If the risk of hose whipping exists, consider the use of guards and restraints.
Fire and explosions from conveyed fluid: All hydraulic fluids, including many designated as "fire resistant," are flammable (will burn) when exposed to the proper conditions. Fluids under pressure that escape from system containment may develop a mist or fine spray that can explode upon contact with a source of ignition (e.g., open flames, sparks and hot manifolds). These explosions can be very severe and cause extensive property damage, serious injury or death. Care should be taken to eliminate all possible ignition sources from contact with escaping fluids, fluid spray or mist resulting from hydraulic system failures. Select and route hoses to minimize the risk of combustion.
Fire and explosions from static-electric discharge: Fluid passing through hose can generate static electricity, resulting in static-electric discharge. This may create sparks that can ignite system fluids or gases in the surrounding atmosphere. Use hose rated for static conductivity or a proper grounding device. Consult manufacturers for proper hose and coupling selection.
Burns from conveyed fluids: Fluid media conveyed in certain applications may reach temperatures that can burn human skin. If there is risk of burns from escaping fluid, consider guards and shields to prevent injury, particularly in areas normally occupied by operators.
Electrical shock: Electrocution can occur when a hose assembly conducts electricity to a person. Most hoses are conductive. Many have metal fittings. Even nonconductive hoses can be conduits for electricity if they carry conductive fluids. Certain applications require hose to be nonconductive to prevent electrical current flow. Other applications require the hose to be sufficiently conductive to drain off static electricity. Hose and fittings must be chosen with these needs in mind.
Air and gaseous applications: The covers of hose assemblies that are to be used to convey air and other gaseous materials must be pin-perforated. These perforations allow gas that has permeated through the inner tube of the hose to escape into the atmosphere. This prevents gases from accumulating and blistering the hose.
Employers are encouraged to provide training for personnel working with and around hoses under pressure.
This article is an excerpt from NAHAD's Hose Safety Institute Handbook©, which provides industry-leading performance standards for hose assembly specification, design, handling and management.
For additional information or to purchase NAHAD's Hose Safety Institute Handbook©, visit the NAHAD website at www.nahad.org or contact Debbie Mitchell at dmitchell@nahad.org.