This article is about Magnetic Gauges / Switches Material Selection Criteria & Design For Level Measurement of Instrumentation and Control Systems as per International Codes and standards for Commercial Buildings, Plants and Refinery Projects.
Magnetic Gauges / Switches Material Selection Criteria & Design
Material Receiving General Checklist for Instrumentation & Control
Purchase Order and Instrument specification sheet criteria shall be confirmed and compared with instrument stainless steel tags / labels and nameplates, and shipment checked for damage, prior to acceptance of the shipment
Verify that all the instruments are from technically acceptable vendors. (Attachment 1)
At least two independent liquid level gauging devices shall be provided for each tank. One of these gauging devices shall be displayed in the manned control house supervising the tank farm.
An independent high liquid level alarm shall be installed in each tank. Thealarm shall be set to allow operating personnel sufficient time to stop incoming flow without overflowing the tank. The use of a high level flow shutoff device shall not nullify the requirement for a high level alarm.
With the exception of relief valve piping, all instrument connections (except thermo wells) smaller than 50 mm (2 in) shall be provided with excess flow check valves or restricting orifices having an orifice size not greater than 3.175 mm ( 1/8 in), or spring return valve with fusible link.
“Magnetic Level Indicator Gauges (MLI) may be used for services in which:
a) Sight level gauge glass assemblies are not recommended for the
measurement of dangerous or toxic fluids”
“Magnetic Level Indicator Gauges (MLI) may be used for services in which:
b) Glass breakage would be likely”
“Magnetic Level Indicator Gauges (MLI) may be used for services in which:
c) Sight level gauge glass can be obscured or coated due to the
nature of the process fluid”
“MLI assemblies shall be installed only in areas that are free of physical
forces or materials that would adversely affect the magnetic operation
of the system.”
“MLIs shall not be installed in dirty or plugging service where debris or
buildup can cause float sticking.
International Codes and Standards for Magnetic Gauges / Switches Material
- Flow Nozzle Material Selection Criteria Design & Flow Measurement
- Venturi Tube Material Selection Criteria Design & Flow Measurement
3. SAES-J-002 – Technically acceptable instruments, 23 June 2008
4. SAES-J-300 – Level, 27 February 2007
5. SAES-B-057 – Safety Requirements: Refrigerated and Pressure Storage Vessels, 29 June 2005
6. Standard Drawing Orifice plates 990-J- AB-036094 Sheet 1 Rev 16 and Sheet 2 Rev 01
7. PIP PCCFL 001 – Flow Measurement Criteria , August 2006, Process Industry Practices Process Control.
1. Attachment 1: Technically Acceptable Instruments – SAES-J-002