1. PURPOSE…………………………………………………………………..2. GENERAL 3. ADDENDA The following section, subsection numbers refer to API 682
Section 1- General
1.1 Scope …………………………………………………………………1.3 Conflicting Requirements 1.4 Definition of Terms 1.5 Referenced Publications ……………………………………….
Section 2 – Steel Design
2.1 Standard Seal Type and Arrangements 2.3 Steel Chamber and Glands …………………………………..2.4 Shaft Sleeves 2.5 Mating Rings 2.6 Flexible Elements…………………………………………………
Section 3 – Materials 3.2 Seal Faces 3.5 Secondary Sealing Components …………………………….
Section 4- Accessories 4.1 Auxiliary Piping System 4.3 Quench Systems (Group II)……………………………………4.4 Cooling-Water Systems (Group III) 4.5 Accessories and Auxiliary System Components 4.6 Barrier/Buffer Fluid and Seal Flush Positive Circulating
Devices…………………………………………………………………….4.7 Buffer Gas Supply System for Non-Contacting
Seals
Section 5- Instrumentation Section 6- Inspection, testing and preparation for shipment…………
6.1 General 6.2 Inspection
6.4 Preparation for shipment ………………………………………..Section 7- Manufacturer Data
7.2 Proposals
1. Purpose
American Petroleum Institute (API) standard API 682, First Edition, October 1994 is adapted as SABIC
Engineering Standard with the following addendum to supplement requirements.
2. General
Equipment manufactured to this standard shall conform to API 682, First Edition, except as modified
herein, or as set forth on Data Sheets, Project Specifications or Purchase Order.
3. Addenda
The following section/paragraph numbers refer to API 682, First Edition.
Section 1 – General
1.1 Scope
1.1.1 Add the following paragraph:
This standard covers the minimum requirements for Seals and Sealing Systems for pumps which comply
with SABIC Standards G01-S06 and G15-S01. Mechanical seals for pumps built to other standards are
not required to meet this specification.
1.1.5 Add the following new paragraph:
This SABIC Standard includes requirements for application and design of dry-running mechanical seals.
Although API 682 First Edition, does not specifically addresses dry-running seals, many of the underlying
concepts of seal application and design in API 682 apply equally to these type of seals.
1.1.6 Add the following new paragraph:
Mechanical seals and associated support systems shall be supplied by vendors qualified by experience to
manufacture the proposed units. To qualify, the vendor must have manufactured at least two (2) seals of
comparable pressure, temperature, diameter, speed and materials for fluids having comparable
properties. These seals shall be in service for at least one (1) year and shall be performing satisfactorily.
1.3 Conflicting Requirements
Add the following paragraph:
Any conflict(s) between this standard and other standards, engineering drawings, and contract documents
shall be resolved at the discretion of SABIC.
1.4 Definition of Terms
1.4.36 Change ‘Purchaser’ to ‘SABIC’ throughout the standard.
1.4.42 Modify the following term:
‘Seal manufacturer’ to ‘Vendor’. This modification is applicable throughout the standard.
1.5 Referenced Publications
1.5.4 Add the following new paragraph:
The following documents are part of this addendum. The latest issues, amendments, and supplements to
these documents shall apply unless otherwise indicated.
SABIC Engineering Standards(SES)
G01-S06 Centrifugal Pumps for Heavy Duty Services
G15-S01 Positive Displacement Rotary Pumps
R02-E01 Thermocouples
R03-E05 Pressure Switches
R03-E06 Pressure Gauges
R04-E06 Level Guages
Section – 2 Seal Design
2.1 Standard Seal Types and Arrangements
2.1.9 Add the following new paragraph:
The inner seal for dual non-contacting dry Gas Seals shall be a reverse pressure balance design in
accordance with paragraph 2.1.6 comment.
2.3 Seal Chamber and Glands
2.3.2 Add the following paragraph:
Unless otherwise specified or an alternate approved by SABIC, traditional seal chambers shall be supplied.
2.3.9 Modify the second paragraph as follows:
Where the vapor pressure of the pumped liquid exceeds 100 Kpa (14.7 Psia), at 38 °C, a second plugged
connection shall be provided to permit direct measurement of seal chamber pressure.
2.3.11 Add the following sentence:
The flush inlet arrangement for single seals with stationary flexible elements shall be designed to avoid
erosion of the stationary seal elements.
2.3.19.1 Modify the paragraph as follows:
Process connections shall be at least 3/4 in NPT. SABIC approval shall be required for
1/2 in NPT
connections.
2.3.20 Add the following sentence:
Fixed throttle bushings are required for all dual seals. If a throttle bushing does not fit due to axial space
limitations, SABIC approval shall be required for not using a throttle bushing.
2.3.22 Add the following new paragraphs:
When specified, dry-running secondary containment seal, either contact or lift-off face design, installed in
tandem with a primary mechanical seal, shall be supplied.
The secondary seal is housed in the gland and is suitable for operation at full seal chamber conditions, but
normally operates dry or wet below the seal leakage pressure switch setting. Secondary containment seals
shall be face-type seals, rated for 25,000 h of operation in a gas or liquid environment at a pressure up to
the set point of the seal leakage detection pressure switch and 500 h of operation in a liquid environment
up to the maximum seal chamber conditions.
2.4 Shaft Sleeves
2.4.2 Add the following sentence:
The use of sleeve-on-sleeve design shall not be allowed.
2.4.10.3 Modify the paragraph as follows:
Design using nine or more set screws to drive and axially position the shaft sleeve shall require SABIC
approval.
2.4.10.4 Add the following sentences:
Seal sleeves that are axially fixed by a split ring are not normally required. They shall be supplied when
recommended by the seal vendor and approved by SABIC.
2.4.12 Add the following new paragraph:
Shaft sleeves shall be hardened to 55 HRC under dynamic secondary sealing elements in contact with the
pumped liquid.
2.5 Mating Rings
2.5.2 Modify the second sentence as follows:
Clamped seal faces shall not be used.
2.6 Flexible Elements
2.6.1 Add the following sentence:
The use of a single spring Type A design shall require SABIC approval.
Section 3 – Materials
3.1.2 Add the following paragraph:
The vendor shall ensure that the materials are compatible with the fluids that the seal may contact.
3.2 Seal Faces
3.2.3 Modify the second sentence as follows:
Mating rings of self sintered silicon carbide (SSSic) shall require SABIC approval.
3.5 Secondary Sealing Components
3.5.4 Add the following new paragraph:
Secondary sealing elements selection shall be based on the specified maximum temperature.
Section 4 – Accessories
4.1 Auxiliary Piping Systems
4.1.3 Add the following sentence:
When seal leakage detection is specified, a plugged pressure gauge connection shall be provided
between the seal chamber and the pressure switch.
4.1.7.f Add the following item:
Piping connections shall be provided to permit removal of the mechanical seal flush piping.
4.1.7.g Add the following new item:
Valved vent and drain connections shall be braced.
4.1.8 Add the following paragraph:
Socket welded and threaded fittings shall conform to ASME B16.11, class 3000 or class 6000
corresponding to flange rating ASME 900 or 1500. Butt weld fittings shall conform to ASME B16.9.
Flanged connections shall conform to ASME B16.5.
4.1.9 Add the following sentences:
Socket welded connections shall be preferred over seal welded threaded connections. Threaded
connections shall be seal welded. Seal welds on threaded connections shall cover all exposed threads
after the joint has been tightened.
4.1.15 Add the following sentence:
Wall thickness of piping of sizes 2 in and less shall be of Schedule 80.
4.1.17 Add the following sentence:
When joining piping by butt-welds, the maximum allowable misalignment at the inside of piping shall not
exceed 1.5 mm (
1 /16 in) at any point of the circumference of the joint.
4.1.18 Add the following sentence:
Unless otherwise specified, threaded plugs shall be of 316 L stainless steel.
4.1.19 Add the following sentences:
All valves shall be in accordance with API 602 Class 800 or ANSI B16.34 with respective rating as
required. For throttling service, globe or needle valves shall be furnished.
4.3 Quench Systems (Group II)
4.3.c Add the following sentence:
For hydrocarbon service above 150 °C, an anti-coking baffle for steam quench shall be provided.
4.4 Cooling-Water Systems (Group III)
4.4.1 Modify Table 7 as follows:
Unless otherwise specified, the cooling water system design shall be based on following temperatures:
Maximum inlet temperature: 36 °C
Maximum temperature rise: 10 °C
4.4.2 Decision:
Galvanized pipe shall not be required.
4.4.3 The decision is as follows:
Closed sight flow indicators shall be supplied in each seal cooling water outlet line.
4.4.5 Add the following new paragraph:
Unless otherwise specified, Stainless Steel A312, grade 316L or Copper-Nickel (
90
/
) pipe shall be used
in sea water cooling service.
4.5 Accessories and Auxiliary System Components
4.5.3.3 Add the following paragraph:
10
The vendor shall ensure that tubing material is compatible with the flush liquid.
4.5.4.1.5 Add the following sentence:
Filling systems supplied by the seal vendor shall be designed such that the reverse pressure capability of
the seal is not exceeded when filling the reservoir.
4.5.5.2 The decision is as follows:
The vendor shall review the barrier/buffer fluid selection and comment on the effect of the selection on seal
operating life.
4.6 Barrier/Buffer Fluid and Seal Flush Positive Circulating Devices
4.6.1 The decision is as follows:
Unless otherwise specified, a positive circulating arrangement utilizing an internal circulating device shall
be supplied when dual seals or flush plan 23 is required. Internal circulating devices integral to the seal
shall be preferred to external circulating pumps or external flush fluid supply for dual seals or single seals
utilizing a plan 23 flush arrangement. The seal vendor shall review each seal application and determine if
external supply or circulation is required, and state the reason (for example, the need for increased cooling)
for the equipment.
4.6.4.2 The decision is as follows:
Pump and seal vendors shall be responsible for the performance of their equipment at the specified field
conditions. Therefore, the external flush fluid selection shall be reviewed by both vendors.
4.7 Add the following new subsection:
4.7 Buffer Gas Supply System for Non-Contacting Seals:
4.7.1 Add the following new paragraph:
Minimum components for the buffer gas supply system for Non-Contacting (Lift-off) dry gas seals shall be a
pressure regulator, coalescing filter, flow meter, check valve, low pressure switch and pressure gauge.
These components shall be mounted on a steel plate with all items arranged for ease of maintenance and
replacement. The pressure regulator, pressure gauge and pressure switch shall be best sized for seal
operating pressure to be in the middle third of the operating range. The coalescing filter shall be 2-3 micron
nominal rating. The flow meter range shall be a minimum of three (3) times the nominal seal buffer gas leak
rate specified by the vendor.
Section 5 – Instrumentation
5.2.2 Modify the paragraph as follows:
Dial temperature gauges shall be installed in each buffer/barriers fluid seal reservoir or seal flush cooler 2
in (50 mm) below the low level alarm (LLA). Dial temperature gauges shall not be installed in the
inter-connecting tubing lines.
Section 6 – Inspection, Testing and Preparation for Shipment
6.1 General
6.1.4 Add the following sentences:
Requirements for QA Inspection/Testing and documentation shall be as specified on Mechanical Seal
Data Sheets. Witnessed inspection(s) or test(s) shall be prearranged with SABIC.
6.2 Inspection
6.2.3 Add the following sentence:
As a minimum, liquid penetrant or magnetic particle inspection shall be required for pressure containing
welds on buffer fluid piping components.
6.4 Preparation for shipment
6.4.3.8 Add the following sentence:
Small components that are not installed in the pump shall be tagged, wrapped in waterproof material and
packaged in box and fastened to the pump base plate.
Section 7 – Manufacturer Data
7.2 Proposals
7.2.2 Add the following items:
Unless otherwise specified, the vendor’s proposal shall include following information:
h. The values for face generated heat and process heat soak for the seal size, type and speed.
i. The curves or other data showing the seal chamber pressure for the entire range of pump operation.