Hose Coupling Maintenance Program Essential for Preserving Safety

June 1, 2001
ALTHOUGH carriers typically operate a preventive maintenance program for trucks and tank trailers, hose couplings are frequently neglected. Dan Burke

ALTHOUGH carriers typically operate a preventive maintenance program for trucks and tank trailers, hose couplings are frequently neglected. Dan Burke of Dixon-Bayco urged members of the National Tank Truck Carriers Safety Council to emphasize this area of maintenance, which has big safety ramifications for carriers.

“Damaged or misapplied hose couplings and related tanker items aren't uncommon,” he said. “Unless they are caught by a trained eye, these hazards may linger until an accident happens, threatening not only equipment, but also the well-being of personnel and the public.”

Since the early 1990s, Dixon Valve & Coupling has conducted over 2,000 in-plant safety surveys, in part, to determine how hose couplings can be improved to help fleets and manufacturing plants reduce accidents. Many of these plants have found that the surveys helped them reduce reportable incidents, recordable injuries, and helped curb spiraling insurance cost. In its next safety step, the company introduced coupling installation workshops for maintenance personnel. The workshops are designed to enhance carriers' safety training and preventive programs, Burke said.

Establishing written procedures for mechanics is one of the most important aspects of a pro-active preventive maintenance program. “Written procedures can help insure that couplings are installed correctly to help prevent accidents and fulfill requirements for ISO certification,” he added.

Those procedures should cover the care, maintenance, and inspection of cam and groove couplings. They should also describe how to change broken cam arms, methods of securing arms, and how to inspect gaskets.

“An on-going program of inspection of cam and groove handles, rings, and pins must be included to eliminate problems,” he said. “Damaged, missing, or broken parts of fittings must be replaced. These parts are durable, but not indestructible. Every effort must be made to avoid using fittings with damaged or missing cam arms.”

In addressing bolt-style clamps, he said that proper selection, installation, and maintenance are key factors in their safe use on hose assemblies. When installing these clamps, the individual body sections should never be allowed to come in contact with each other. There must always be an even amount of rubber hose between the clamp sections for the clamp to be fully functional.

Bolt-style clamps can only fulfill their design capabilities if the bolts are tightened to their recommended torque. The bolts can be retorqued, but it is not recommended that they be reused, as they are designed for a single bend only.

“Do not replace old bolts with any other grade bolts, as the bolts are designed to bend properly when torqued, and to aid in the proper installation of the clamp,” he said.

He pointed out that the Occupational Safety and Health Administration requires safety clips for all Chicago-style couplings. However, some companies find that compliance on usage isn't all that good.

“Dixon now has several types of safety clips because people want options, and we're interested in finding what plant personnel will use,” he said.

Burke recommended hydrostatic pressure testing at periodic intervals on hose assemblies and strongly discouraged the use of air pressure testing due to the explosive forces that air testing can unleash.

On the subject of dry bulk tank trailer equipment, Burke noted that the driver, while unloading, should not adjust the dry bulk air relief valve setting. He cautioned that drivers might try to tamper with the equipment in order to speed up the unloading process.

“Tampering with the air relief valve may cause premature failure of the expensive blower or in a worst-case scenario, even cause the tanker to explode from over-pressuring.”

More information about hose coupling safety can be found on the Dixon web site at www.dixonvalve.com. Hose assembly testing procedures are also available from the Rubber Manufacturers Association.