Gage Glasses

IPE Engineering Practice IPE-EP-12-1-18

Document number: IPE-EP-12-1-18 · Section: 12 — Instruments and Controls

SCOPE

Flat glass level gages shall be supplied in strict accordance with EP 12–1–18 DS, this Practice, and the referenced standards and publications.
Where special features or improvements over the Practice are required as determined by the Owner, or Owner’s Engineer, these shall be specified on the Instrument Data Sheets and shall be adhered to by the Vendor.
Any deviation from this Practice must be approved by the procedure described in EP 1–1–3.
A revision bar indicates all changes made to this Revision.

2.0 REFERENCES

The following codes and standards shall be considered as part of this Practice. All documents shall be the latest editions in force on the date of issuance of this Practice.

STANDARDS AND PUBLICATIONS

IPE Engineering Practices
EP 1–1–3 Deviations to IPE Engineering Practices EP 12–1–1 Control Systems EP 12–1–2 Supplemental Requirements for Control Systems EP 12–1–18 DS Gage Glasses Data Sheet
ASME
B 1.20.1 Pipe Threads General Purpose (Inch)
ASTM
A193 Alloy–Steel and Stainless Steel Bolting Materials for High Temperature Service A194 Carbon and Alloy Steel Nuts for Bolts for High–Pressure and High Temperature Service
NFPA
70 National Electrical Code

DEFINITIONS

Contractor - Company or business that agrees to furnish materials or perform specified services at a specified price and/or rate to the Owner.
Inspector - A Inflection Point Engineering, LLC . appointed engineer or inspector.
Manufacturer - The recipient of a direct or indirect purchase order for materials and/or equipment. In this context, a direct order is one issued to a manufacturer by a contractor or the Owner. An indirect order is one issued to a manufacturer by a vendor (recipient of a direct order) for materials, fabricated components, or subassemblies.
Owner - Inflection Point Engineering, LLC .

4.0

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Owner’s Engineer - A Inflection Point Engineering, LLC appointed engineer.

Purchaser - The party placing a direct purchase order. The purchaser is the Owner’s designated representative.

Vendor - Recipient of a direct purchase order.

DESIGN AND MATERIALS

General

Gage columns shall consists of one or more flat glass sections of the type and the visible length specified on the Instrument Data Sheets. Multiple sections are to be assembled on a one piece liquid chamber. When multiple sections are assembled on a one piece liquid chamber, the visible length shall be the measured distance from the bottom visible portion of the lower section to the top visible portion of the upper section.

Each component of the gage glass column shall be suitable for the design conditions specified on the Data Sheets. Chambers shall have a minimum rating of 270 psig at 600oF for size 9 glass. Gage glasses shall be used in services only up to one-half of their manufacturer’s rating and not to exceed 1000 psig.

Pipe threads shall be tapered and shall conform to ASME B1.20.1.

All plugged connections shall be furnished with cylindrical pipe plugs approximately 2 inches long and of the same type materials specified for the gage glass column.

Design and materials not specified herein shall be in accordance with the Manufacturer’s standards suitable for the operating and design conditions specified on the Data Sheets.

Gage Glass Sections

Gage glass sections shall be of the transparent type (double glass) as specified on the Data Sheets.

Gage glass bodies and covers shall be of carbon steel construction unless otherwise specified.

Bolting shall be of ASTM A193, Gr. B7 steel and nuts shall conform to ASTM A194, Gr. 2H steel unless otherwise specified.

Glass shall be of the mechanical and thermal shock resistant type.

Connection style shall be as specified on the Data Sheets. All connections shall be internally threaded 3/4 inch NPT.

When two side connections are furnished 180 o apart at the same end of a section, one of the side connections shall be furnished plugged.

Vent connections shall be furnished for upper side connected glasses and drain connections shall be furnished plugged.

When illuminators are specified, they shall be of the plastic solid wedge type designed to give an even diffusion of light over the entire length of the gage glass. Illuminators shall be furnished with mounting brackets and shall be provided with lighting fixtures meeting the National Electrical Code (NEC) area classification requirements of Class 1, Group B, C, & D, Division 2. Illuminators shall be furnished with clear lamps, medium base with minimum 50 W rating. Lamps shall be suitable for operation with 120 Volt, 60 HZ power.
When ”non-frosting” blocks are specified, they shall be of the transparent plastic type covering full width of vision slot and suitable sealed to the glass to prevent accumulation of condensate on the glass. Depth of non-frosting plastic blocks shall be determined by the Vendor based on the service conditions as specified on the Data Sheet.

5.0 INSTRUCTIONS FOR DATA SHEET

The following numbers correspond to the line numbers on the Data Sheet, EP 12-1-18DS.

1.	Show identification number
2.	Vessel Identification number or service. Separate data sheets shall be used for each vessel.
3.	Specify transparent, reflex, tubular, magnetic.
4.	Specify size, and style of process connections
5.	Specify location to top connection (side, back, top)
6.	Specify location of bottom connection
7.	Specify the length of the visible glass area
8.	Specify the overall length of the gage glass to the centerline of connections
9.	Specify vent connection size
10.	Specify drain connection size
11.	Specify the minimum rating
12.	Specify the material of gage glass chamber and connection
14.	Specify yes if required with the gage glass
15.	Specify yes if required
16.	Specify yes if required
17.	Specify yes if required
18.	Specify yes if required
21.	Specify the maximum operating pressure
22.	Specify the minimum operating pressure
23.	Specify the maximum operating temperature
24.	Specify the minimum operating temperature
25.	Specify the process service or fluid name
27.	Fill in after selection is made

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