34-SAMSS-622

Previous Issue: 30 November 2003 Next Planned Update: 6 January 2014 Revised paragraphs are indicated in the right margin of 12 Primary contact: Brell, Austin on 966-3-8747219

Copyright©Saudi Aramco 2009. All rights reserved.

Materials System Specification

34-SAMSS-622 6 January 2009 ESD Systems - Electromagnetic Relay

Instrumentation Standards Committee Members Al-Juaib, Mohammed Khalifah, Chairman Tuin, Rienk, Vice Chairman Al-Dakhil, Tareq Khalil Al-Faer Al Sharif, Hisham Mohammed Al-Harbi, Ahmed Saad Al-Jumah, Yousif Ahmed Al-Khalifa, Ali Hussain Al-Qaffas, Saleh Abdal Wahab Al-Sahan, Fawaz Adnan Al-Saleem, Hesham Salem Chetia, Manoj Ell, Steven Tal Fadley, Gary Lowell Falkenberg, Anton Raymond Grainger, John Francis Mahmood, Balal Mathew, Vinod Qarni, Mahdi Ali Trembley, Robert James

Saudi Aramco DeskTop Standards Table of Contents 1 Scope............................................................. 2 2 Conflicts And Deviations................................ 2 3 References..................................................... 2 4 Environmental Conditions.............................. 3 5 Electrical Requirements................................. 3 6 Design............................................................ 4 7 Component Selection..................................... 8 8 Cabinet Construction.................................... 10 9 Documentation............................................. 11 10 Testing.......................................................... 11

Document Responsibility: Instrumentation 34-SAMSS-622

Issue Date: 6 January 2009

Next Planned Update: 6 January 2014 ESD Systems - Electromagnetic Relay

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1 Scope

This specification together with the purchase order, functional specification document

and appropriate specification sheets prescribes the minimum requirements for

electromagnetic relay emergency shutdown (ESD) systems.

Excluded from this specification are solid state-based ESD systems (refer to 34-

SAMSS-621), and programmable controller-based ESD systems (see 34-SAMSS-623).

2 Conflicts and Deviations

2.1 Any conflicts between this specification and their applicable Saudi Aramco

Materials System Specifications (SAMSSs), Engineering Standards (SAESs),

Standard Drawings (SASDs), or industry standards, codes and forms shall be

resolved in writing by the Company or Buyer Representative through the

Manager, Process & Control Systems Department of Saudi Aramco, Dhahran.

2.2 Direct all requests to deviate from this specification in writing to the Company or

Buyer Representative, who shall follow internal company procedure SAEP-302

and forward such requests to the Manager, Process & Control Systems

Department of Saudi Aramco, Dhahran.

3 References

Material or equipment supplied to this specification shall comply with the latest edition

of the references listed below, unless otherwise noted.

3.1 Saudi Aramco References

Saudi Aramco Engineering Procedures

SAEP-302 Instructions for Obtaining a Waiver of a

Mandatory Saudi Aramco Engineering

Requirement

SAEP-1634 Factory Acceptance Test

Saudi Aramco Materials System Specifications

34-SAMSS-820 Instrument Control Cabinets - Indoor

34-SAMSS-821 Instrument Control Cabinets - Outdoor

Saudi Aramco Library Drawing

DB-950096 Elementary Diagram - Relay Based ESD Systems

http://standards/docs/Samss/PDF/34-SAMSS-621.PDF



http://standards/docs/Saep/PDF/SAEP-302.PDF





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Saudi Aramco Inspection Requirements

Form 175-344300 Relay Based Emergency Shutdown Systems

Saudi Aramco Forms & Data Sheets

8020-825-ENG Instrument Specification Sheet for

Electromagnetic Relays

NMR-7924-1 Non-Material Requirements for Relay Based ESD

Systems

3.2 Industry Codes and Standards

The Instrumentation, Systems & Automation Society

ANSI/ISA S84.01 Application of Safety Instrumented Systems for the

Process Industries, Annex B (Informative):

Safety Instrumented Systems Design

Considerations

National Fire Protection Association

ANSI/NFPA 70 National Electrical Code (NEC)

National Electrical Manufacturers Association

NEMA ICS 5 Industrial Control and Systems Control-Circuit

and Pilot Devices

3.3 Engineering Units

Unless specified otherwise all dimensions and measurements shall be in the

“International System of Units” (SI), and may be followed by the equivalent

value in conventional units between brackets.

4 Environmental Conditions

The ESD systems shall be suitable for operation in the environmental conditions stated

in 34-SAMSS-820 for indoor applications or 34-SAMSS-821 for outdoor applications.

5 Electrical Requirements

5.1 Unless otherwise specified, ESD equipment shall be powered from separate Saudi

Aramco supplied UPS branch feeders at 120 VAC (tolerance of 110-126 VAC)

and 60 Hz (± 2 Hz) which are over-current protected.

5.2 The panel, materials, and equipment required for the electrical wiring and

installation within the control panel shall be suitable for use in the specified area

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../Forms/8020825.XLS

../Forms/NMR79241.PDF

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classification as defined by ANSI/NFPA 70, National Electrical Code (NEC),

Article 505.

5.3 Wiring and cabling shall be designed and installed in accordance with

ANSI/NFPA 70 National Electrical Code (NEC).

5.4 ESD system components shall be listed, labeled, and conform to UL, FM, CSA

or CENELEC guidelines.

5.5 Unless otherwise specified the power supply voltage for logic relays and

input/output devices shall be 24 VDC.

Commentary Notes:

If the ESD voltage source is fed directly from a UPS battery bank that is charged by a rectifier, as opposed to being supplied by a DC/AC inverter, the vendor shall include DC/DC regulators and filters as necessary to maintain the logic voltage within the tolerances and limits of the specified relays.

If the vendor is responsible for providing redundant DC power supplies as an integral part of the ESD system, load sharing shall be provided. Redundant DC power supplies that are connected to a single output ESD power bus shall use diode auctioning to provide output isolation and to insure bump-less transfer in the event of a single power supply failure. A means shall be provided for visually monitoring the health of the auctioneering diode.

6 Design

The overall logic design for the relay based ESD system shall follow the general

guidelines of ANSI/ISA S84.01 Informative Annex B. A relay based ESD system shall

be designed to a safety integrity level (SIL) of SIL-2, unless superseded by more

stringent requirements listed in the purchase requisition, specification or instrument

specification sheet.

A relay ladder logic drawing and wiring diagram shall be provided as part of the design

documentation. The wiring diagram shall follow the guidelines provided in the Library

Drawing DB-950096, Elementary Diagram Relay Based ESD System.

Commentary Note:

Each rung of ladder logic must be uniquely numbered and identified by an associated equipment number and logic description. Each rung must include cross-references for each relay element used throughout the entire ladder network.

The ESD system shall be designed to fail-safe i.e., any single failure or defect in system

hardware shall cause the affected output(s) to de-energize immediately to the designated

failure position unless otherwise specified in the ISS, logic drawings or Purchase Order.



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Commentary Note:

ESD input signals typically originate from process-activated switches (with dry, potential-free contacts) or trip amplifiers. ESD outputs normally drive status indicators, annunciators, data loggers, solenoid valves or motor control relays.

The relay logic system design shall follow the general criteria of (a) – (d) below:

a) Contacts open on coil de-energization due to loss of coil circuit continuity, loss of

electrical power, open-circuit failures or interruptions, or removal of relays or

their subassemblies.

b) Selected relay armature mechanisms should preferentially employ gravity dropout

or dual retraction springs.

c) Relay contacts must be of material and voltage/current rating specified in Section 7.

d) Energy limiting load devices are installed across relay output contacts to prevent

the contacts from welding closed, and to suppress arcs caused by the collapsing

magnetic field currents generated by inductive loads (e.g., motor control relays or

solenoid valves).

The vendor shall configure the inputs, logic and outputs to perform the operational and

process requirements shown in the basic logic diagrams, cause and effect matrix,

elementary wiring diagrams, relay ladder logic diagrams and approved ESD functional

specification supplied by the Buyer or his representative.

6.1 Input Section

Individual conductors from each ESD initiating (field) switch, emergency

push/pull button, or reset push-button wiring shall be terminated on input section

terminal strips and isolated from ESD logic wiring (or contact replication relays)

via an input isolation relay.

6.1.1 Input Relay

Each input relay shall have a minimum of three (3) form C contacts,

wired in the following manner:

a) 1 (NO) contact: To ESD system logic wiring or to an associated

contact replication/multiplication relay if necessary. Note the

requirements for input bypass switch wiring (paragraph 6.1.2)

associated with this contact.

b) 1 (NO) contact: To be routed to an external annunciator.

c) 1 (NO) contact: To be routed to an external sequence of events

recorder or data logger.




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Contacts (b) & (c) for connection to an annunciator, event recorder or

data logger shall be wired to dedicated terminals within the relay cabinet

for Buyer's interconnection to external devices.

Commentary Note:

If a distributed control system (DCS) or PLC functions as the ESD annunciator, event logger or historian, a single contact from the input relay section may be used, rather than allocating two separate contacts. In this case each input relay shall have a minimum of two (2) form C contacts (DPDT).

6.1.2 Input Bypass Switches

A manually operated input bypass switch shall be installed for each ESD

system input (except for ESD push/pull buttons or reset pushbuttons) to

facilitate maintenance and testing. The input bypass switch shall be

wired in parallel with the first (NO) contact of the input isolation relay.

Input relay contacts for interconnection to annunciator, indicating lights,

sequence of event recorder or data logger shall not be bypassed. Each

input bypass switch shall have an extra set of spare (NO) contacts, wired

to internal relay cabinet terminals for Buyer's interconnection to an

external annunciator or as an input to an external DCS or PLC (i.e., to

perform alarm, sequence of events and annunciation).

Each input bypass switch shall have a yellow BYPASS indicating light

emitting diode (LED) that illuminates when the switch is in the bypass

position.

6.2 Contact Multiplication/Replication section

If additional contacts are needed to build the required ESD logic than can be

provided by the single input isolation relay, additional contact multiplication

relays shall be provided in a separately fused, contact replication section. These

additional relays should be located as close as practical to the input relay.

6.3 Logic Section

The logic section shall be arranged so that relays and logic for related pieces of

process equipment are physically grouped together. All ESD logic shall be

designed such that after a shutdown due to open field switch contacts, open fuse

connections, loose wiring or ESD logic de-energization, the ESD logic stays in

the de-energized state. The ESD logic remains in a de-energized state until

permissives have been met or failed components have been resolved and the

logic is manually reset.




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6.3.1 Manual Reset

Each ESD system shall have a manual reset push-button or equivalent

reset device.

6.3.2 Lamp Test

All ESD relay cabinet indicator LEDs, shall be configured with lamp test

logic circuitry. LED test outputs for remote or panel mounted indicating

lights shall be wired to separate relay cabinet terminals for Buyer's

connection.

Exception:

LEDs or other lamps that are integral to a manufactures electronic component (e.g., trip amplifier, or electronic timer/counter) do not require the lamp test button.

6.4 Output Section

The relay cabinet output section shall isolate field devices and associated wiring

from ESD internal logic voltage and wiring via fuses or over current protective

devices. All field output devices shall be powered from the ESD system power

supply, unless otherwise specified on the elementary wiring diagrams, ladder

diagrams or logic diagrams supplied by the Buyer.

6.4.1 Output Bypass Switches

ESD output bypass switches are not to be provided unless the purchase

order or relay cabinet specifications explicitly calls for their

implementation.

Commentary Note:

When ESD output bypass switches are specified, only the specific identified outputs shall be provided with a manually operated, key-locked, output bypass switch to facilitate maintenance and testing. The output bypass switch logic shall not prevent ESD outputs from being de-energized in response to activating an ESD push/pull-button for the system.

6.4.2 Outputs to annunciators, indicating lights, sequence of event recorder or

data logger shall not be bypassed. Each output bypass switch shall have

separate set of (NO) contacts, wired to separate relay cabinet terminals

for the Buyer's interconnection to an external annunciator.

Each output bypass switch shall have a yellow BYPASS indicating LED

that illuminates when the switch is in the bypass position.




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6.5 Manual Emergency Shutdown Switch Logic

Each ESD relay system shall be provided with terminals for Buyer's connection

to a local or remote emergency shutdown push/pull button(s). When the

normally closed ESD pushbutton circuit is broken, the ESD system logic de-

energizes, causing relay outputs to fail to their respective de-energized position,

regardless of any bypass switch that might be activated. If relay cabinets

themselves are equipped with ESD buttons, they shall be protected from

accidental operation by a guard, shroud or cover.

6.6 Grounding

ESD systems shall have their negative or return-neutral side grounded (i.e.,

referenced to an instrument system ground). Approval for ungrounded or

floating systems must be obtained in writing from the Manager, Process &

Control Systems Department of Saudi Aramco, Dhahran.

Commentary Notes:

1. Ungrounded or floating ESD systems shall only be used where modifications to existing ungrounded systems equipment are being considered. ESD systems shall be configured either as a grounded or an isolated (ungrounded) system configuration, but not within the same I/O structure.

2. Ungrounded or isolated ESD systems utilizing floating DC 'field' input and output circuits shall incorporate a commercial, modular type of ground fault detection system (GFD) to monitor potential ground leakage currents within field. GFD circuitry shall continuously monitor floating electrical circuits in field wiring and activate a visual alarm indicator when resistance to earth falls below a nominal 1 K ohms. GFD modules (if used) shall be installed in a location readily accessible to maintenance personnel.

7 Component Selection

All components and assemblies shall be designed and spaced to operate reliably with

only natural-draft ventilation. All components and subassemblies shall be at least

„industrial grade‟ and „field-proven‟ for at least two years.

7.1 Installation materials

Installation materials, wiring, terminations and other components shall be

selected in accordance with 34-SAMSS-820 or 34-SAMSS-821, unless

otherwise specified in the Purchase Order.

7.2 ESD Relays

ESD relays shall comply with the minimum requirements of this specification,

unless superseded by more stringent requirements listed in specification Form






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8020-825-ENG. Relays installed in outdoor cabinets shall be hermetically

sealed. If a specific relay is not identified on the relay specification sheet or in

the Purchase Order, the vendor shall propose a suitable relay for Buyer's

engineer's evaluation and approval, based on the minimum established

requirements below.

The following information shall be marked on the relay: manufacturers name,

contact configuration, coil voltage and applicable listed marks.

7.3 The basis for relay selection shall be proven reliability and performance in

critical ESD service.

a) ESD relays shall have a minimum mean time-to-failure (MTTF) of 2 x 105

hours (23 years) or greater.

b) Mechanical Cycle life (min.): 20 x 106 (AC); 40 x 10

6 (DC)

c) Contact Qty & Form (min.): 2/3 Form C Contacts, DPDT/3PDT

d) Contact Rating: 10 amp – A600 (AC); N600 (DC)

e) Rated Contact Voltage (min): 240 VAC

f) Contact material: AgCdO

g) Ambient Temperature rating: 50°C (Indoors), 70°C (Outdoors)

h) Protection Category: IP 40 (Indoors) IP 54 (Outdoors)

i) Coil Pickup/Dropout Time (max.): 20 msec

j) Coil Power Indicator: LED for each relay coil

k) Contact Protection-Output Relays: Diode/Varistor/RC network

l) Insulation Resistance (min): 500M ohms (at 500 VDC)

7.4 Fused terminals

Fused terminals shall be used for the positive (hot/line) side of all field or

marshaling cabinet I/O wiring which interfaces with the ESD cabinet. This

includes ESD system inputs, outputs, indicating lights, power distribution and

annunciator interconnections. If the negative side of relay coils are ungrounded

(e.g., floating), they shall be provided with fused terminals equipped with blown

fuse indicators.

7.5 Bypass Switches

Bypass switches and/or push/pull buttons shall comply with NEMA ICS 5, Part

5. Switch contacts shall be sealed or encapsulated.

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8 Cabinet Construction

Design, construction and wiring of the ESD relay cabinets shall be in accordance with

34-SAMSS-820 or 34-SAMSS-821 unless superseded by the requirements of this

specification.

8.1 Assembly and Mounting

Relays and subsystem components shall preferably be installed on DIN rails or

mounting plates, with restraint or relay locking clips, securely fixed within the

cabinet(s).

8.2 Internal ESD DC Power Supply

DC power supplies installed within ESD cabinets shall always be mounted at the

top of the cabinet, above any relays or subsystem components.

Specific requirements for internal ESD-DC power supply systems shall be as

specified in the Purchase Order. DC power supplies shall be linear, non-

switching type, consisting of a main and one backup power supply unit, each

capable of assuming 120% of the full load. “Full load” shall be interpreted as

the maximum power consumption within the ESD systems. The dual power

supply units shall be identical to minimize spare parts requirements.

8.2.1 Power Supply Monitoring

Power supply health status, voltage and current shall be indicated on the

front side of each power supply unit. In the event of a failure of one of

the power supply modules a power supply failure shall be indicated on

the front of the ESD relay panel as well as remotely to an operator

console.

8.2.2 Power Supply Protection

Power supply units shall have their own current-limiting devices as well

as over-voltage and transient protection for the primary side. Diode

isolation, voltage regulation and current-limiting circuitry shall be used

on the secondary. Crowbar shunting or current limiting output circuits

are not permitted.

8.2.3 Power Restoration

ESD relay logic shall remain in the de-energized position when power is

applied or restored to via the power supplies. Manual RESET action will

be required to energize logic relays, provided permissive circuits are

enabled.






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9 Documentation

Required Vendor's Documentation: Prior to commencement of a Factory Acceptance

Test (FAT), the Vendor shall provide the following Non-Material Requirements

(NMR's) to designated Company representatives, preferably in electronic format:

a) A Bill of Materials for the ESD relay panel.

b) ESD logic in relay ladder logic format (or equivalent) including all pertinent

comments describing the logic functions.

c) An index of all I/O points including individual tag name(s).

d) A narrative describing the operation and sequence of the logic system (based on

the buyer's original logic and or narrative description).

e) Cabinet construction, assembly and interconnecting wiring diagrams and cabinet

arrangement drawings showing front and rear views of the enclosure with a view

of installed equipment including relay layout.

f) Factory Acceptance Test (FAT) document detailing the set-up and procedures for

a functional test of the ESD relay panel.

10 Testing

The Vendor shall submit a copy of his standard relay systems test procedures and

standard burn-in procedures for all devices or subassemblies that contain relays and

electronic components such as trip amplifiers or ground fault detection components.

SAEP-1634 shall be adhered to in the development of the FAT procedures.

Saudi Aramco testing and inspection form 175-344300, logic or cause and effect

diagrams, in conjunction with the ESD functional specification document shall be used

as the basis for a Factory Acceptance Test (FAT) of all vendor supplied ESD

equipment.

Factory Acceptance Testing (FAT)

10.1 The Vendor is responsible for providing all test equipment required to perform

the tests described in this section. In addition, he shall perform full functional

tests based on the FAT procedures and confirm that any problems have been

resolved prior to inviting Buyer's representative for the Buyer-witnessed FAT.

10.2 During the FAT test the complete ESD system including all cabinets,

termination-marshaling panels or assemblies, and associated equipment will be

checked and verified against approved construction drawings and wiring

diagrams.


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10.3 The tests shall demonstrate the functionality of each individual input and output

point and associated logic elements making up the logic structure of the relay

ESD system. This includes all discrete, analog or timer/counter elements, sub-

assemblies, or modules.

10.4 Wire tagging and terminations shall be checked against wiring diagrams and

“Tug” tested. (A tug test involves physically stressing a wire termination to

determine whether it has been crimped and terminated properly. The intent is

not to break wiring or stress insulation or components but to test the integrity of

the termination).

10.5 All discrepancies noted in the FAT shall be resolved to the satisfaction of the

Buyer. Results of the FAT test shall be documented by a written report,

supported by the FAT procedure used.

Revision Summary

6 January 2009 Revised the “Next Planned Update.” Reaffirmed the content of the document, and reissued with minor revisions.

34-SAMSS-622

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