ASME and PED Requirements for

Drum Level

Instrumentation

2017

Presented by: Amir Hedayatnia

Clark-Reliance Corp.

Topics

• Gage Glasses and Remote Reading Instruments

• ASME Code Section I Requirements for Drum Level Instrumentation (boilers that operate > 1 Bar G)

• Water Columns(Standpipes) and Water Gage Isolation Valves

• Requirements for Isolation Valves

• ASME CSD-1 Low Water Cutouts Applications

• ASME Section VII Recommendations for Proper Care of Power Boilers

• Common Code Violations (Illustrated)

• PED Requirements

ASME Code General Terms

Gage Glass

Direct Reading Indirect Reading

Remote Level Indicator

Direct Reading Gage Glasses

Tubular Glass

to 17 Bar G Bi-Color

(Ported)

to 206 Bar G Flat Glass

(Transparent)

to 132 Bar G

Prismatic

(Reflex)

to 24 Bar G

End-to-End Reflex Gage Glasses

Are Permitted

- - PG.60.1 Clarifies

the use of multi-

section gages

without overlap, due

to the light

refraction principle

- Transparent Type

Multi-section gages

do require a 25 mm

minimum overlap

Flat Glass Transparent Type Water Gage

Glasses with LED Illumination

Typical View of Water Level with no obstructions in the

viewing area. The gage must be illuminated, as needed

for the level to be readily visible by the operator.

Structural Webs are Prohibited

From Flat Glass Gages Designs

- These Webs may

mask the actual

location of the water

level

- The risk of Masking

the level is enhanced

on elevated gage

glass installations

Bi-Color Water Gage Principle of Operation

Water shows GREEN Steam shows RED.

Bi-Color Gages must be outfitted with an

illuminator to be Code Compliant

(Light refracts differently through water than steam

with glasses on specific angles)

Remote (Indirect) Level Indicator

Technologies

Differential Pressure

Conductivity

Magnetic Guided Wave

Magnetic Water Level Gages are Permitted up to 62 Bar G

Magnetic Level Gage (equipped w/ 4-20 transmitter)

For Process

(Typical)

For

Power

Boilers

Indication Scale

External switches

Are not permitted

for control purposes,

such as

Low Water Cutouts

(PG-12 and PG-60)

Code Issues and Concerns for the Use of

Magnetic Level Gages on Boiler Drums Acceptable as an acceptable Indirect Reading for applications range

up to 62 Bar G), Ref: PG12.2

The Indication Scale must follow ASME guidelines, Ref: PG-60.3.2 &

PG60.3.3

May not be used to support a water Gage glass, due to prohibition of

stainless steel construction for water columns. Ref: PG-12.3

No accessories are permitted to be attached for control purposes

(No Trip limiting switches). This device must be used for indication only. Ref: PG-60.1.1.4

The use of a Magnetic Level Gage does not replace the Code requirement for a Water Gage Glass on any Power Boiler Drum designed to meet Section I of the ASME Code

Section I Requirements

Operating up to 27 Bar G

One Direct Reading Gage Required (which must be kept continuous service)

Operating over 27 Bar G

Two Direct Reading Gages in service

or Two Remote (Indirect) Level Indicators

On Continuous Display for the

Operator and One Direct Reading Gage (Which may be Isolated but kept in serviceable condition)

or

One gage glass in continuous service with a camera

system combined with an Indirect Remote Level

Indicator

Water Gage Requirements:

Section I Requirements for Gage Glass Placement

Level “A” = Lowest Permissible Water Level, at which there will be no danger of overheating the boiler

Note: 4 and 6 must not intersect 1 and 2

1- Lower side

steam conn.

2- Upper side

water conn.

3- Level A

4- Low vision

5- Drum

6- High vision

7- Steam conn.

Section I - References

Water Columns (PG-60.2)

25 mm (1” min) connections for water column to boiler (PG-60.3.4)

20 mm (3/4” min) drain connection (PG-60.2.3)

Stainless Steel construction for water columns is prohibited (PG-12.3)

A Code stamp is not required on water columns, because they along

with level instruments are considered to be fittings (PG-11)

Water Level Indicators (PG-60.1) Water Gage Glass Requirements (PG-60.1.1)

20 mm (3/4” min) connection size for Remote (Indirect) level indicators (PG-60.3.4)

Highest & Lowest visible permissible water level (PG-60.1)

Isolation and Drain Valve Requirements (PG-60.1.2)

25 mm (1”) Gage overlap requirement for Transparent Gages (PG-60.1) - 1996

Transverse or Structural Webs are prohibited from the construction of Transparent

(Flat Glass) Water Gages, which may obstruct view of the level(PG60.1) - 2009

Stainless Steel is permissible for Gage Glass Body construction (PG-12)

Magnetic (Float Type) Level Gages are permitted up to 62 Bar G (PG-12) - 2007

Gage Cocks not required PG60.4 – 1991 (See image above )

Section I Valve Requirements

• Isolation valves installed between the drum

and a water column are optional and when

installed they must be locked open, to

prevent unauthorized use.

• Isolation (shut off) and drain valves must be

installed for any level indicating instrument

(Ref: PG-60.1.2)

• Drain valves must have an unrestricted 6 mm

(¼”) minimum opening

Globe Valves for Isolation

In-line flow prevents sediment or condensate traps, which can lead to false level indication with traditional Globe valves

Correct Incorrect

Globe type valves are permitted if the lowest edge of the seat is at least 25% of the port diameter.

(Ref: PG-60.3.7)

Specifying Ball Checks on Water

Gage Valves • Ball Checks are not mandatory on ASME Applications

• Ball Checks are mandatory on PED (European EN standards) and IBR (India) Applications

• Ball Check Valves (Reference: “Automatic Shutoff

Valves” in the Appendix of the ASME Boiler Code) and defines the design requirements for this User OPTION.

• Consider the application, before specifying Water Gage Valves with the Ball Check feature. The use of Chain operators improve safety by operating from a distance.

Ball Check Specifications, when Applied

Must have a

vertical rising

ball in lower

valve to prevent

trap of water in

gage glass

Typical upper

Ball check

shown

Always Install Chain

Operated valves for

Operator and Plant

Safety

PG.60.1.2 requires a

means to operate when

the valves are 2 meters

above the operating

floor or platform

ASME Section VII - Recommended Guidelines for the Proper Care of Power Boilers

• Check water level in 2 or more instruments prior to start up and verify when a deviation is observed

• Keep Water Gage Glasses clean and easy to read, confirm there is no deviation that could be mistaken as water level

• Water Gages should be properly illuminated for easy observation

• Excessive blow down may cause premature wear of the gage internals

• Verification of high and low water alarms is critical to the prevention of carryover or damage to drum internals

Blowdown Procedure

Bypass Low Trip during this procedure

Common ASME Code Violations

and Concerns

• Isolated inoperable water gages

• Missing water gage glasses

• Missing illumination from water gages

• Inadequate display of remote level

indicators in the control room combined

with isolated gages

Code Violations

A drain valve is missing on this lower water gage

valve

Magnetic Level Gage Scale

extends below lower connection,

it will always indicate some level

Photo of Serious Installation Error

Code Violation and Operation Risk to Boiler

Photo of Corrected Installation

Violation and Remedy

Before and After

ASME Summary

Requirements

• Code compliant material is used in all

pressure parts

• All welding procedures and personnel

are qualified

• All instruments are hydrostatically

tested at 1-1/2 times their design

pressure

PED Requirements for

Instrumentation

• EN12952-7 Subsection 5.4 requires a minimum of two Water Gage Glasses on all Power Boilers or one water gage combined with 2 Remote Level Indicators

• Connecting Tubes (Piping) between the

Boiler and the Water Level Indicator must have a minimum inside diameter of 20 mm

When the water connecting lines are longer than 750 mm, the inside diameter of the connecting piping must be at least 40 mm

Water connecting piping from the Boiler must always be horizontally oriented to the Water Level Indicators

PED Requirements for

Instrumentation

• 5.4.6 All Water Gage Glasses must be fitted with an internal Self-Closing Safety Device (Ball Checks in the Water Gage Isolation Valves)

• 5.4.5 On each Gage glass the Lowest Permissible Water Level shall be marked “LWL”

• 5.4.4 The lower limit of the gage glass range shall be at least 30 mm below the lowest permissible level

• The “open position” on Water Gage Cocks (Valves) shall be indicated

Compliance with PED

For All PED Categories:

• We conduct a PED Assessment using a

Program to evaluate the pressure and

volume of the instrument to determine

the PED Hazard Category

• Prepare a Declaration of Conformity

for Article 4 Par. 3 (most level

instrumentation), or Category I or II

Compliance with PED

• All Categories must be manufactured with

material including EN10204 3.1 rating

• On the MTR. All materials must be traceable

back to the European Community and

meeting all PED requirements.

• The final PED package (MDR) must be

retained for 10 years

Compliance with PED

Risk Analysis Form required for Category I and II includes:

Job # (Clark-Reliance Order Number)

Item # (Clark-Reliance Item Model Number)

Internal Pressure (pressure from the Hazard Calc.)

Operating Temp. (Saturated Steam Temp.)

Static Pressure & Volume of Contents:

- (Design Pressure & Volume of contents)

- This Form is signed by the Product or Quality

Manager

Compliance with PED

Complete a Final Internal and External Inspection Report

including:

– ‘Check’ drawings that go through our Shop with the

production documents.

– Each workstation initials they have witnessed or

completed ‘their’ responsibility for the equipment, we

are self certifying. This includes Dimensions, Welds,

Testing and Painting procedures

– These Check List drawings go to our Quality Dept. for

review and “sign-off”

Compliance with PED

Information Included in the Final PED Package:

• Weld Procedures (ASME – CAT. I or PED – CAT. II)

• Welders Qualifications

• Drawings with Weld Maps

• C-R ISO Registration Certificate

• Hydrotest Reports

Compliance with PED

Additional items that may apply (Cat I & II):

• Calibration Certificates for Torque Wrenches and Hydrotest Gauges

• Calibration PMA – Particular Material Appraisal required for each material on the order (Category I and II)

• Our QC Manual for Receiving and Inspection

• Instruction Manuals must be “CE” specific.

• Category I and II require PED tags attached to the instrument

Compliance with PED

Additional Requirements For Category II

• Must use PED Certified Welders

• Must have their PED Qualifications

• PED Welding Procedures must be reviewed by

an EU recognized Inspection Agency

Essential Information Required

for the Evaluation of

Applications

Specifications:

- Design Pressure

- Indication Range

- Vessel connection Size

- Vessel Connection Centers

- Application Environment

(Indoor or Outdoor)

Specify LED Illumination for Water Gage Glass applications for optimum view of the level Specify multiple technologies for Remote Indication to maximize reliability and protect against common mode failure

Recommend proper maintenance and routine inspection of these critical instruments

General Summary Recommendations for

Technology on Drum Level

Instrumentation

• All piping from the drum to the water

level instruments is to be insulated for the following reasons:

1. Provides safety for plant personnel 2. Increases level accuracy 3. Reduce excess condensate formation to improve instrument service life • Piping from Drum to Level Instruments

should be kept to a minimum < 2M

Recommendations for Level

Instrument Piping

Summary Your time and attention to this information is

appreciated, along with your contributions to

Operator and Plant Safety of Power Boilers

Questions

Request a copy at Clark-Reliance.com

Reliance Boiler Trim