Intrinsic Safety & Gauging Thermometers
ThermoProbe gauging thermometers are considered to be “intrinsically safe” as originally manufactured. In the event that any component(s) associated with electrical or electronic portion of the device fails, there will not be sufficient energy to cause an ignition while in a flammable atmosphere. The materials that are used to construct the enclosure and probe assembly are unlikely to cause a spark if they were ever to contact any other materials. The materials used are specific stainless steel and aluminum alloys, and plastics. In addition to the intrinsic safety of the circuit board and enclosure materials, low resistivity plastics are used so that static electricity does not accumulate on any surfaces. Even though all these precautions are taken and accounted for by the various testing entities, we also include a bonding (grounding) strap for all our gauging thermometers. Pumping action in a tank or sloshing in a marine vessel can cause a difference in electrical potential between the liquid product and external objects. For this reason the bonding strap should always be used before any objects are inserted into a vessel containing flammable contents.
Depending on the particular model ThermoProbe instruments are:
- UL913 (North America) The insignia for this standard is the (UL Mark) with appropriate markings.
- CSA (North America) The insignia for this standard is the (CSA) or (ULc) with appropriate markings.
- CENELEC EN 50 020 (Europe) The insignia for this standard is the (Ex) with appropriate markings.
- TIIS (Japan)
Entities which have evaluated ThermoProbe products to intrinsically safe standards are:
- Underwriter Laboratories, Northbrook IL USA
- Canadian Standards Association, Rexdale, Ontario, CANADA
- KEMA, Arnhem, NETHERLANDS
- NEMKO, Oslo, NORWAY
- Yokagawa Research Institute, Tokyo, Japan
We are periodically inspected by representatives of these organizations to ensure that ThermoProbe gauging thermometers are built to written criteria as established through their respective evaluations.
Model TP-7 & 8 are listed for Class I, Division 1 Groups A,B,C, and D.The highest Intrinsically Safe Classification in North America. These models are also can be obtained with the European classification EEx ia IIB.
Model TP-5 can carry the European classification EEx ia IIB T3 as well as Class I, Division 1 Groups C and D for North America.
Static Dissipation
ThermoProbe Inc. uses probe cable with a non-stick coated outer jacket that is extremely resistant to melting and chemical damage. Despite the good properties of the non-stick coated surface it can accumulate static electricity like other plastics. To minimize the accumulation of static on the cable, we have the non-stick coated jacket impregnated with a high percentage of electrically conductive additive. Although this is not required by any of the safety agencies, we feel this extra precaution is worth the added expense.
As with our cable, we also use static dissipating plastic for our TP-7 case.
The models TP-5 and TP-8 are constructed with an aluminum case so static accumulation is not an issue with material.
All models are equipped with a bonding (grounding) cord and clip to ensure that any electric potential is neutralized. The bonding clip should always be attached to a bare metal point (with continuity to the vessel) before using the instrument. This procedure should be followed before anything enters into a vessel of flammable material.
CE Marking for Europe
We have had our TP-7 and TP-8 successfully evaluated to the electromagnetic requirements of the EMC Directive 89/336/EEC.
Recommended Standards for Petroleum Gauging
American Petroleum Institute http://www.api.org
Tel: +1 202.682.8375
Chapter 3, Tank Gauging
Std 2545, Method of Gauging Petroleum and Petroleum Products, October 1965
Chapter 3.1A, Manual Gauging of Petroleum and Petroleum Products, First Edition, December
Chapter 3.1B, Standard Practice for Level Measurement of Liquid Hydrocarbons in Stationary Tanks by Automatic Tank Gauging, First Edition, April 1992; Reaffirmed, January 1997
Chapter 3.2, Tank Gauging--Gauging Petroleum and Petroleum Products in Tank Cars, First
Chapter 3.3, Level Measurement of Liquid Hydrocarbons in Stationary Pressurized Storage Tanks by Automatic Tank Gauging, First Edition, June 1996
Chapter 3.4, Standard Practice for Level Measurement of Liquid Hydrocarbons on Marine Vessels by Automatic Tank Gauging, First Edition, April 1995
Chapter 3.5, Standard Practice for Level Measurement of Light Hydrocarbon Liquids Onboard Marine Vessels by Automatic Tank Gauging, First Edition, March 1997
Chapter 7, Temperature Determination
Chapter 7.1, Static Temperature Determination Using Mercury-in-Glass Tank Thermometers,
Chapter 7.2, Dynamic Temperature Determination, Second Edition, March 1995
Chapter 7.3, Static Temperature Determination Using Portable Electronic Thermometers,
Chapter 7.4, Static Temperature Determination Using Fixed Automatic Tank Thermometers
Chapter 17, Marine Measurement
Chapter 17.2, Measurement of Cargoes On Board Tank Vessels, First Edition, July 1990;
Chapter 17.2A, Closed and Restricted Measurement, First Edition, November 1995
ISO Switzerland http://www.iso.ch
ISO/DIS 4268
Petroleum and liquid petroleum products -- Temperature measurements -- Manual methods \
Publisher Unknown, location in U.K.
International Safety Guide for Oil Tankers and Terminals