CSA ANSI LNG 4.4 pdf free download
CSA ANSI LNG 4.4 pdf free download.Relief valves for hot water supply systems.
Relief element
Pressure — that part of a pressure relief valve which, when acted upon by a pressure in excess of that for which the relief valve is set, permits the relief valve to open and relieve the pressure in the system to which the relief valve is attached.
Temperature — that part of a combination temperature and pressure relief valve (T&P valve) which operates to open the T&P valve and permit the escape of the liquid from the system when the temperature rises above a predetermined point and allows the T&P valve to close again when the temperature returns to normal.
Vacuum — that part of the vacuum relief valve which, when acted upon by a vacuum in excess of that for which the relief valve is set, permits the relief valve to open and admit air into the system to which the relief valve is attached.
Relief valve — a safety valve designed to forestall the development of a dangerous condition by relieving either pressure, temperature, or vacuum in a hot water supply system.
Pressure relief valve — a valve that automatically opens a relief vent, when pressure reaches a predetermined value and reseats again when the pressure returns to normal.
Combination temperature and pressure (T&P) relief valve — a valve that automatically opens a relief vent when either the pressure or temperature reaches a predetermined value and reseats again when the pressure or temperature returns to normal.
Vacuum relief valve — a valve that automatically opens a vent for relieving a vacuum when the vacuum reaches a predetermined value, and closes again when the vacuum dissipates.
Relieving pressure — the pressure at which a relief valve will pass water at the specified rate. (See Clause 5.2)
Relief vent (drain) — the opening in a relief valve through which steam or water is discharged or, in a vacuum relief valve, through which air is drawn in, when the relief valve functions.
Reseating pressure — the highest pressure, in a system with reducing pressure, at which a relief valve reseats to a drip tight condition.
Reseating temperature — the temperature at which the temperature element of a combination pressure and temperature relief valve (T&P) allows the T&P valve to close.
Set pressure — the rated opening pressure marked on a relief valve.
Set temperature — the rated opening temperature marked on a relief valve.
Setting — that particular pressure, temperature, or vacuum at which the valve is adjusted or designed to function.
Temperature steam rating — the steam discharge capacity in Btu per hour marked on a relief valve.
Valve — as used in this Standard, that portion of the relief valve actuated by the relief element, which (1) opens or closes the passage of the relief vent, or (2) shuts off the main gas supply.
4 Construction 4.1 General
4.1.1 Sectional or assembly drawings, or blueprints of all relief valves submitted for test shall be supplied in triplicate by the manufacturer. These drawings and notes shall give full details of the operation of the device.
4.1.2 The temperature relief element of a T&P valve shall be of the automatic reseating type.
4.1.3 The construction of a relief valve shall be such that, in the course of normal handling and installation, it will not become damaged to an extent that would prevent its continued compliance with this Standard.
4.1.4 The construction of parts not covered by this Standard shall be in accordance with reasonable concepts of safety, substantiality, and durability. AlI specifications as to construction set forth herein may be satisfied by the construction actually prescribed or such other construction as will provide at least equivalent performance.
4.1.5 When the inlet of a relief valve includes a special purpose adapter, the adapter shall be a permanent part of the relief valve body and the relief valve shall comply with this Standard with the adapter in place.
CSA ANSI LNG 4.4 pdf download.
