Handling and Installing Valves

  • Identify the common requirements for valve nameplates
  • Identify the correct procedure for storing and handling valves.

Valve Nameplates

As there are many different types of valves and different standards that are applicable for each type of valve it is not possible to give a definitive list of the exact information required to be marked on a valve. For example a safety

valve requires very specific information which must be carried on the valve. Marking is mandatory on both the shell, usually cast or stamped, and the nameplate, which must be securely attached to the valve. A general summary of the

information required is listed below:

On the Shell

Size designation.

Material designation of the shell.

Manufacturer’s name or trademark.

Direction of flow arrow.

On the Identification Plate

Set pressure (in bar g for European valves and psi g for ASME valves).

Number of the relevant standard (or relevant ASME stamp).

Manufacturer’s model type reference.

De rated coefficient of discharge or certified capacity.

Flow area.

Lift and over-pressure.

Date of manufacture or Serial reference number.

Other Information that May Be on Different Types of Valves

Surface finish if applicable

Heat Number

PED and ATEX classification

Details the valve marking system required by TÜV


Storage and Handling of Valves

Proper storage and protection should be considered early in the selection process, before the valve is shipped. Typically, manufacturers have packaging standards that are dependent upon the destination and intended length of storage before installation. Because most valves arrive on site some time before installation, many problems can be averted by making sure the details of the installation schedule are known and discussed with the manufacturer at the time of valve selection. In addition, special precautions should be taken upon receipt of the valve at the final destination. For example, the valve must be stored in a clean, dry place away from any traffic or other activity that could damage the valve.

Installation Instructions for Valves

Valves form a critical part of any piping system and because they are integral to the system construction they need to be installed in parallel with the piping installation. This differs from other critical equipment such as instruments and large piping components which can be installed close to the end where they are not exposed to risk of damage from construction activities. As there are many different types of valves it is not possible to give a definitive list of installation instructions for every valve. The following list is meant only as a guideline, please consult the specific valve manual and your supervisor for specific instructions:

Intended use: Refer to the Installation and Maintenance Instructions,name-plate and Technical Information Sheet, to ensure that the product is suitable for the intended use/application. Inspect the valve before use and ensure that it is in safe working order and that there was no damage during shipping.

Access: Ensure safe access and if necessary a safe working platform (suitably guarded) before attempting to work on any valve. Arrange suitable lifting gear if required.

Hazardous liquids or gases in the pipeline: Consider what is in the pipeline or what may have been in the pipeline at some previous time. Consider: flammable materials, substances hazardous to health, extremes of temperature.

Hazardous environment around the product: Consider: explosion risk areas, lack of oxygen (e.g. tanks, pits), dangerous gases, extremes of temperature, hot surfaces, fire hazard (e.g. during welding), excessive noise, moving machinery.

Be Sure the Pipeline Is Clean: Foreign material in the pipeline could damage the seating surface of the valve or even obstruct the movement of the valve plug, ball, or disk so that the valve does not shut off properly. To help reduce the possibility of a dangerous situation from occurring, clean all pipelines before installing. Make sure pipe scale, metal chips, welding slag, and other foreign materials are removed. In addition, inspect pipe flanges to ensure a smooth gasket surface.

The system: Consider the effect on the complete system of the work proposed. Will any proposed action (e.g. closing isolation valves, electrical isolation) put any other part of the system or any personnel at risk? Dangers might include isolation of vents or protective devices or the rendering ineffective of controls or alarms. Ensure isolation valves are turned on and off in a gradual way to avoid system shocks.

Pressure systems: Ensure that any pressure is isolated and safely vented to atmospheric pressure. Consider double isolation (double block and bleed) and the locking or labeling of closed valves. Do not assume that the system has depressurized even when the pressure gauge indicates zero.

Temperature: Allow time for temperature to normalize after isolation to avoid danger of burns. Tools and consumables: Before starting work ensure that you have suitable tools and/or consumables available. Use only genuine replacement spare parts for seal replacements

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Permits to work: All work must be carried out or be supervised by a suitably competent person. Installation and operating personnel should be trained in the correct use of the product according to the Installation and Maintenance Instructions. Where a formal ‘permit to work’ system is in force it must be complied with. Where there is no such system, it is recommended that a responsible person should know what work is going on and, where necessary, arrange to have an assistant whose primary responsibility is safety. Post warning notices’ if necessary.

Handling: Manual handling of large and/or heavy valves may present a risk of injury. Lifting, pushing, pulling, carrying or supporting a load by bodily force can cause injury particularly to the back. You are advised to assess the risks taking into account the task, the individual, the load and the working environment and use the appropriate handling method depending on the circumstances of the work being done.

Residual hazards: In normal use the external surface of the product may be very hot. If used at the maximum permitted operating conditions the surface temperature of some products may reach temperatures of 232°C (450°F). Many products are not self-draining. Take due care when dismantling or removing the product from an installation (refer to ‘Maintenance instructions’).

Freezing: Provision must be made to protect products which are not self-draining against frost damage in environments where they may be exposed to temperatures below freezing point.

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Maintenance of Valves

Please note, always follow the valve manufacturer’s recommended maintenance instructions. Optimization of a valve service life depends on an effective maintenance philosophy and program. Three of the most basic approaches to maintenance are:

Reactive – Action is taken after an event has occurred. Wait for something to happen to a valve and then repair or replace it.

Preventive – Action is taken on a timetable based on history; that is, try to prevent something bad from happening.

Predictive – Action is taken based on field input using state-of-the-art, non-intrusive diagnostic test and evaluation devices or using smart instrumentation. Although both reactive and preventive programs work, they do not optimize valve potential as reactive maintenance can be very disruptive to an operating plant and preventative maintenance can result in valves being serviced before they require it. The most effective approach is predictive maintenance which consists of four distinct modes:

Fault Detection A majority of valve maintenance effort is spent in monitoring valves while in service to detect the occurrence of a fault. When a fault is identified, the maintenance process transitions to fault discrimination.

Fault Discrimination During this mode, valve assets are evaluated to determine the cause of the fault and to establish a course of corrective action.

Process Recovery Corrective action is taken to fix the source of the defect.

 

 

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