Knife Gate Valve Specification: RFQ Checklist and Required Engineering Data

Knife Gate Valve RFQ Checklist: Minimum Data to Send First

A manufacturer can often prepare a preliminary technical offer before every project document is complete. The first RFQ still needs enough information to prevent the quotation from being built on unsuitable or hidden assumptions.

Project Identification, Tag Number and Quantity

Start with the information that identifies where the valve belongs in the project:

• project or plant name;
• valve tag number;
• line number or equipment reference;
• required quantity;
• new installation or replacement duty;
• enquiry, budget quotation or final procurement stage;
• required documentation language and submission format.

A tag number is more than an administrative reference. It keeps clarifications, datasheets, drawings and document revisions connected to the correct service.

For a replacement project, include the existing nameplate, drawing, installation photos and the reason for replacement where available. Matching the nominal size alone does not establish interchangeability.

Minimum Process and Pipeline Data

The first technical enquiry should normally include:

• process media;
• solids concentration or an available process description;
• particle or fibrous content;
• nominal line size;
• operating and design pressure;
• maximum differential pressure where known;
• operating and design temperature;
• pipeline orientation;
• flow or pressure direction;
• connection type and flange drilling;
• required shutoff direction.

Descriptions such as “slurry service” or “wastewater” are too broad for an engineering RFQ. A more useful entry identifies the solids concentration with its stated basis, the approximate maximum particle size, particle shape and any known abrasion or settling tendency.

Two services with the same general name can require different valve designs because their particle size, chemistry, solids loading and settling behaviour are different.

Minimum Actuation and Document Requirements

State whether the valve will be:

• manually operated;
• pneumatically actuated;
• electrically actuated;
• hydraulically actuated.

For automated valves, provide the available power or control utility, expected operating frequency, required fail behaviour and basic accessory requirements.

Also identify which documents are required with the quotation and which will be required after an order. This prevents a technically plausible valve from reaching the approval stage without the dimensional, material or control information needed for final review.

Minimum Knife Gate Valve RFQ Checklist

This is a minimum enquiry checklist, not the final engineering specification. A formal RFQ should later add detailed media data, materials, pressure-direction requirements, actuation duty, installation constraints, inspection requirements and document status. The RFQ Data Maturity section explains how these requirements develop from preliminary enquiry to final approval.

Buyer Inputs vs Manufacturer-Confirmed Knife Gate Valve Data

A technically controlled RFQ separates project requirements from product-selection results. When these two data groups are mixed, different suppliers may quote against different assumptions, making technical comparison difficult and allowing unresolved issues to remain hidden until drawing review or order approval.

What the Buyer or EPC Team Should Define

The buyer should define the required operating conditions and project constraints, including:

• what flows through the valve;
• what solids or fibers are present;
• what pressure acts across the closed gate;
• whether reverse pressure can occur;
• what shutoff function is required;
• how often the valve will operate;
• how it will be installed and accessed;
• which utilities are available;
• which project standards and documents are required.

These are application requirements. They should remain valid even when different manufacturers propose different valve constructions.

What the Valve Manufacturer Should Select and Confirm

Based on the application data, the manufacturer should confirm:

• suitable knife gate valve design;
• sealing direction and seat arrangement;
• body, gate, seat, packing and other component materials;
• product pressure and temperature capability;
• actuator type and size;
• required accessories;
• face-to-face, height, width, stroke and weight;
• applicable tests;
• model, reference and document revision.

These are product-specific outputs. They should be supported by a controlled technical offer, datasheet and drawing rather than inferred from a general article or product-family description.

How to Record Clarifications, Assumptions and Deviations

Every quotation assumption that can affect fit, function or document scope should be visible. Examples include:

• solids concentration not provided;
• reverse pressure assumed not to occur;
• operating frequency assumed to be low;
• flange drilling interpreted from the stated piping class;
• actuator utility awaiting confirmation;
• material requirement proposed by the manufacturer rather than specified by the buyer.

If an offer differs from the RFQ, the deviation should be stated directly instead of being hidden in a product code, footnote or general qualification.

Buyer Input vs Manufacturer Response

A sound knife gate valve specification therefore separates what the project requires from what the manufacturer proposes. This makes offers more comparable and exposes assumptions before they become drawing, installation or approval conflicts.

Define the Process Media, Solids and Particle Conditions

“Slurry,” “sludge” or “wastewater” is not a complete process specification. The manufacturer needs enough information to understand how the media may interact with the gate, seat, body cavity, packing and clearing features.

Media Composition, Solids Concentration and Fibrous Content

State whether the media is:

• primarily liquid with suspended solids;
• a high-concentration slurry;
• sludge with fibrous or stringy material;
• abrasive mineral slurry;
• pulp or other fibrous stock;
• ash, powder or dry granular material;
• chemically corrosive liquid containing solids;
• a mixed or variable process stream.

Where possible, provide solids concentration using the same basis used by the process team. Do not provide a percentage without identifying whether it is by weight, volume or another process basis.

For variable service, provide both the normal and maximum expected conditions. The manufacturer should confirm whether the proposed design remains suitable for the most demanding known solids, particle and chemistry condition—not only the average operating case.

Particle Size, Shape, Hardness and Settling Behaviour

Particle information helps the manufacturer assess whether material may:

• collect in the body cavity;
• interfere with the seat;
• pack around the gate;
• increase closing resistance;
• abrade the gate or seat;
• bridge across an opening;
• settle when the line is idle.

Useful information includes:

• approximate particle size range;
• maximum particle size;
• rounded, angular, fibrous or irregular shape;
• relative hardness or abrasiveness;
• density and settling tendency;
• tendency to cake, crystallize or compact;
• presence of foreign debris.

There is no single universal particle-size or solids limit for all knife gate valves. Suitability depends on the selected design, size, seat construction and operating conditions.

Abrasion, Corrosion, Scaling and Chemical Compatibility Data

The specification should distinguish mechanical wear from chemical attack.

An abrasive but chemically neutral slurry may require a different component strategy from a corrosive liquid containing only moderate solids. A fluid that crystallizes or deposits scale may also interfere with the gate and seat even when it is not highly abrasive.

Where relevant, provide:

• pH range;
• chemical constituents;
• chlorides or other corrosive species;
• concentration changes;
• flushing or cleaning chemicals;
• scaling or crystallization tendency;
• expected erosion points;
• process upset conditions.

Particle shape, hardness, settling and chemical data are not optional descriptive details. They may change the manufacturer’s review of the body cavity, gate, seat, packing, liner and clearing arrangement.

Media and Solids Data Fields

The buyer defines the process condition; the manufacturer converts it into a proposed valve construction. Any limitation caused by missing process data should remain visible as an assumption or clarification item.

Define Valve Duty, Shutoff Direction and Service Requirements

The RFQ must describe the task the valve is expected to perform. The product name alone does not establish directional sealing, cycling duty, discharge behaviour or suitability for special operating conditions.

Isolation Duty, Operating Position and Cycle Conditions

Specify whether the valve is intended for:

• normal on-off isolation;
• infrequent emergency isolation;
• discharge from a vessel or hopper;
• operation in a line that remains full;
• operation in a line that can drain;
• frequent cycling;
• normally open service;
• normally closed service;
• occasional partially open operation required by the process.

Do not assume that every knife gate valve is intended for throttling. If the process requires positioning or operation away from fully open and fully closed conditions, state that duty explicitly so the manufacturer can review whether the proposed design is suitable.

Express cycle frequency in practical terms, such as expected cycles per hour, day, week or batch. Higher cycle frequency can affect duty classification, wear review, actuator configuration and accessory selection.

Pressure Direction, Seat Side and Reverse-Pressure Requirements

The RFQ should identify:

• the normal upstream side;
• expected pressure direction when the valve is closed;
• whether pressure can reverse;
• whether shutoff is required in one direction or both;
• whether the valve may operate in a process line with changing pressure direction;
• whether a seat-side orientation is required.

Unidirectional and bidirectional are design characteristics, not labels that should be selected without considering the application.

Where the piping arrangement can create reverse pressure during shutdown, cleaning, pump changeover or vessel operation, that condition should be stated. If reverse pressure is not defined, the manufacturer cannot confirm the required directional shutoff. A proposed unidirectional design should not be assumed to provide the same performance in the reverse direction unless the manufacturer explicitly confirms it.

For installation-level checks on body arrows, SEAT markings and pressure-assisted shutoff, use the knife gate valve flow direction guide before approving the final orientation.

Dead-End, Free-Discharge, Vacuum or Severe-Service Conditions

Special duties must be treated as formal design inputs because they may change pressure direction, sealing arrangement, structural review, actuator requirements or installation assumptions.

Dead-end service may expose one side of the valve to pressure while the opposite side is open or disconnected.

Free-discharge service can create a different outlet condition from a fully pressurized downstream pipeline.

Vacuum service may require separate review of sealing, packing and structural behaviour.

Severe service may involve a combination of abrasion, high solids, frequent cycling, pressure reversal, temperature variation or difficult access.

These conditions should not be added only as a general quotation note. The manufacturer should confirm whether the proposed construction is suitable and whether special options, limitations or installation requirements apply.

Detailed comparison of connection, flow direction, actuation, seat and service designs belongs in the knife gate valve types guide; this specification should only define the duty clearly enough for the manufacturer to select and document the appropriate design.

Specify Size, Pressure, Temperature and Pipeline Interface

A nominal size identifies the line connection, but it does not confirm that a replacement valve will fit, seal or operate within the existing installation envelope.

Nominal Size, Pipe Data and Bore Requirements

Provide:

• nominal valve size;
• pipe outside diameter or pipe specification where relevant;
• piping class;
• line schedule or wall thickness where it affects the interface;
• required bore or port condition;
• existing pipe gap for replacement projects;
• known dimensional restrictions.

A valve with the same nominal size may still have a different face-to-face, flange pattern, bore arrangement or actuator envelope. Replacement projects therefore require more than a nameplate size match.

If face-to-face, flange drilling, bore, open height or actuator envelope is not checked, the replacement valve may not fit the existing pipe gap or surrounding structure and may require additional piping or support modifications.

For a complete fit review, the knife gate valve dimensions guide explains how face-to-face length, flange drilling, open height and actuator envelope should be checked against the GA or certified drawing.

If flow capacity or bore sizing requires detailed engineering, that work should be completed separately rather than inferred from nominal size alone.

When the unresolved issue is bore selection, flow capacity or nominal-size suitability rather than the physical envelope, use the knife gate valve sizing guide as a separate engineering reference.

Operating, Design, Differential and Reverse Pressure

These pressure terms should not be treated as interchangeable.

The actuator may need to move the gate against differential pressure, not merely line pressure. State the maximum differential condition expected during opening and closing.

If upstream and downstream pressures vary independently, provide both conditions or a clear operating scenario.

Temperature Range, Connection, Flange Drilling and Face-to-Face

State normal, minimum and maximum process temperature where relevant. Temperature can affect:

• seat material;
• packing;
• coatings or linings;
• body and gate material;
• actuator accessories;
• environmental protection.

For the pipeline interface, identify:

• wafer, lug, flanged or another required connection;
• flange standard and drilling;
• pressure class or piping class;
• required face-to-face basis;
• gasket and mating-flange restrictions;
• replacement pipe gap;
• whether the valve must be removable without disturbing adjacent equipment.

Where the project specifies ASME flanged interfaces, confirm the applicable size range, pressure class, dimensions and tolerances against ASME B16.5 and the project piping specification rather than relying on nominal size alone.

Exact face-to-face, open height, actuator dimensions and weight should be confirmed from the manufacturer’s controlled drawing.

Specify Materials and Sealing by Component

A single entry such as “stainless steel valve” rarely defines the complete material requirement. The body, gate, seat, packing and other wetted or exposed components perform different functions and may face different wear, corrosion and temperature conditions.

Project-mandated materials, prohibited materials, coating systems and certificate requirements should be stated by the buyer. If the manufacturer is expected to recommend materials, the proposal can only be based on the chemistry, temperature, abrasion and service data supplied with the RFQ. Missing information should remain an assumption or clarification item, not be treated as a final material decision.

Body and Gate Material Requirements

The body forms the pressure-containing structure and may contact the process media. The gate moves through the media, seat and packing area and may experience direct abrasion or corrosion.

The RFQ should therefore distinguish:

• body material;
• gate material;
• gate surface treatment or coating, if required;
• internal lining, if applicable;
• external coating system;
• exposed fastener requirements.

If a project material specification applies, state it clearly. If the manufacturer is asked to recommend materials, provide enough chemistry, temperature and wear information to support the recommendation.

Seat, Liner or Sleeve Requirements

Seat construction can affect:

• shutoff direction;
• leakage behaviour;
• resistance to abrasion;
• chemical compatibility;
• temperature capability;
• maintenance requirements;
• ability to handle trapped solids.

Do not select a seat material from the media name alone. Suitability depends on chemistry, temperature, solids, pressure direction and valve design.

Where liners, sleeves or replaceable wear components form part of the proposed design, the manufacturer should identify them in the technical offer and material schedule.

Packing, Scraper, Stem and Other Project-Critical Parts

Packing seals the moving gate or stem area from the atmosphere. Its selection can be influenced by:

• media chemistry;
• temperature;
• particle migration;
• washdown conditions;
• required adjustment or maintenance access.

Scrapers, flushing arrangements or other clearing features may be relevant for some designs and services. They should be listed as design-dependent requirements, not assumed to exist on every knife gate valve.

Component Material Specification Matrix

For deeper comparison of seat, liner and wetted-component options, review the knife gate valve materials and linings guide, then confirm the final material schedule against the actual service data and project datasheet.

The final component material schedule should be reviewed in the technical offer or project datasheet. It should not be inferred from the product-family name or a general catalog description.

Specify Actuation, Controls and Operating Requirements

Actuator selection depends on the selected valve construction, differential load, operating frequency, required speed, utility conditions and control philosophy—not valve size alone.

Manual, Pneumatic, Electric or Hydraulic Operation

State the required operating method or the project preference.

Manual operation may use a handwheel, gear or another mechanical operator, depending on valve size and operating load.

Pneumatic operation requires the available air-pressure range, air-quality information where relevant and control-accessory requirements.

Electric operation requires voltage, phase, frequency, control signal, enclosure and local-control requirements.

Hydraulic operation requires hydraulic supply conditions and control requirements.

For a broader comparison of manual, pneumatic, electric and hydraulic operation, see the knife gate valve actuation guide; the RFQ should still state the available utility, cycle rate, fail requirement and site constraints.

This article does not select the actuator size. The manufacturer should calculate and confirm it based on the selected valve construction, differential pressure, gate load, cycle requirement and its documented design practice.

Utility Data, Cycle Frequency, Stroke Speed and Fail Position

For automated valves, provide:

• available air-pressure range;
• electrical supply;
• hydraulic supply pressure where applicable;
• required opening and closing time;
• maximum permitted stroke speed, if process-sensitive;
• operating frequency;
• fail-open, fail-closed, fail-in-place or no defined fail-safe requirement;
• emergency or shutdown function;
• ambient temperature;
• hazardous-area classification where applicable.

Knife gate valves do not have one universal default fail position. The required valve state after loss of air or power depends on the project safety requirement, actuator arrangement, air or electrical circuit and control philosophy. It must be stated by the project and confirmed by the manufacturer.

Higher cycle frequency can affect duty classification, component wear and actuator review. It should therefore be included in the RFQ rather than left for the manufacturer to assume.

Limit Switches, Solenoid Valves, Feedback and Manual Override

Accessory requirements may include:

• open and closed limit switches;
• intermediate position feedback;
• solenoid valve;
• filter regulator;
• position transmitter;
• local position indication;
• manual override;
• lockout provision;
• junction box or local control station;
• control-system interface.

The RFQ should distinguish between a simple open-close valve and a valve that must provide confirmed status to a control system.

Actuation and Controls Checklist

Define Installation, Orientation and Maintenance Access

A technically suitable valve can still create installation problems if the RFQ omits the available space, orientation, support and maintenance conditions.

Pipeline Orientation and Installed Pressure Direction

State whether the pipeline is:

• horizontal;
• vertical with upward flow;
• vertical with downward flow;
• inclined;
• part of a vessel or hopper outlet.

Also state the normal pressure direction and intended valve orientation.

Orientation can affect solids settling, gate clearing, actuator support and maintenance access. Final acceptance should be checked against the manufacturer’s installation instructions and the project piping arrangement.

Open Height, Actuator Envelope, Support and Lifting Space

The drawing review should consider:

• face-to-face length;
• closed overall height;
• fully open height;
• actuator width and depth;
• gate or stem projection;
• lifting points;
• required structural support;
• clearance for removal of packing, seat or actuator;
• access for handwheel or local controls.

Do not assume that the pipeline should carry the full weight or operating load of a large actuated valve. Required supports should be addressed in the piping and structural design.

For replacement valves, compare the complete envelope rather than only face-to-face length.

Indoor, Outdoor, Washdown, Hazardous-Area and Maintenance Conditions

State site conditions that may affect the actuator, coating, accessories or maintenance plan:

• indoor or outdoor installation;
• ambient temperature range;
• rain, dust or washdown exposure;
• corrosive atmosphere;
• hazardous-area requirement;
• submerged or frequently flooded location;
• access-platform limitations;
• lifting-equipment restrictions;
• required maintenance side;
• available isolation and depressurization provisions.

What Documents Should the Manufacturer Return?

A technical submission must allow the buyer to verify service suitability, installation fit, control interfaces and document scope. A quotation that states only size, material and price is not a complete engineering response.

Product Datasheet and Technical Offer

The product datasheet or technical offer should identify, as applicable:

• valve model or reference;
• size and connection;
• product pressure and temperature limits;
• body, gate, seat and packing materials;
• actuation method;
• accessory list;
• design direction;
• approximate dimensions and weight;
• applicable tests;
• exclusions and deviations;
• document revision.

A general catalog datasheet can support initial product-range review, but it does not confirm the project-specific configuration. The controlled project datasheet should record the selected materials, actuator, ratings, exceptions and revision status used for technical approval.

The datasheet is a manufacturer output. It should confirm the offered configuration rather than merely repeat the buyer’s RFQ fields.

GA Drawing, Certified Drawing and Dimensional Confirmation

A general arrangement drawing normally provides the configuration and main dimensions needed for layout review. Depending on the project stage, the drawing may still be preliminary.

Before fabrication, installation or final replacement approval, confirm whether the project requires:

• approved GA drawing;
• certified dimensional drawing;
• actuator drawing;
• wiring or pneumatic diagram;
• connection and drilling details;
• centerline-to-top dimension;
• fully open height;
• maintenance-removal clearance;
• weight and center-of-gravity information where relevant.

A preliminary catalog drawing should not be assumed to be the final certified project drawing. Connection, envelope or revision differences between the datasheet and drawing should be closed before approval.

IOM, Material Certificates, Test Reports and Control Documents

The required document package may include:

• installation, operation and maintenance manual;
• material certificates;
• pressure or seat test report;
• inspection record;
• coating documentation;
• actuator datasheet;
• limit-switch or solenoid documentation;
• wiring diagram;
• pneumatic schematic;
• certificate of conformity;
• spare-parts list.

When material inspection documents are required, the purchase order should state the required document type and verification level; BS EN 10204 provides the recognized framework for types of inspection documents for metallic products.

The applicable package depends on the project specification, purchase order and selected valve configuration.

If the purchase specification cites MSS SP-81, first verify that the proposed valve falls within the standard’s stated scope before using it as a design, dimensional or testing basis.

How to Review Deviations From the RFQ

The purpose of technical review is not to decide whether the proposed valve is “generally similar” to the RFQ. It is to identify differences in service suitability, installation interface, document scope and unresolved assumptions before they become approved project data.

Typical review questions include:

• Has the manufacturer accepted the stated media and solids conditions?
• Is the pressure rating valid for the proposed size and configuration?
• Is reverse pressure accepted, excluded or limited?
• Are the seat and packing materials identified?
• Is actuator sizing confirmed for the stated differential pressure?
• Do the connection and drilling match the piping class?
• Are all dimensions marked preliminary or final?
• Are exceptions clearly listed?
• Are required documents included in the vendor scope?

Specification and Vendor Document Responsibilities

A mismatch between the datasheet, drawing and revision register is an approval issue, not a clerical detail. Fit-critical differences should be resolved before manufacturing release.

RFQ Data Maturity: From Preliminary Enquiry to Final Approval

Not every RFQ begins with a fully completed specification. A project may require a budget quotation before the process design is final.

The key is to distinguish preliminary information from approved information and to manage open items visibly.

Minimum Enquiry Data

Minimum enquiry data should be sufficient to identify:

• general service;
• nominal size;
• approximate pressure and temperature;
• broad solids condition;
• required operation;
• quantity;
• known connection requirement.

A manufacturer may issue a preliminary offer based on this information, but assumptions should be listed.

Engineering RFQ and Vendor Clarification

An engineering RFQ should add:

• confirmed process and particle data;
• design and differential pressure;
• pressure direction;
• material requirements;
• connection and drilling;
• cycle and actuator utility;
• installation constraints;
• inspection and documentation requirements.

This is a two-way technical stage. The buyer defines the service and project requirements; the manufacturer reviews them, raises clarification questions and may propose an alternative design or identify assumptions. Fit-critical open items should be resolved or formally recorded before the offer advances to approval.

Vendor Offer, Approved Datasheet and Order-Release Data

Before order release, the project should normally resolve:

• selected design;
• product rating;
• component materials;
• seat direction;
• actuator model and accessories;
• dimensions and weight;
• required tests;
• documentation scope;
• deviations;
• approved drawing status.

Information should not become “approved” merely because it appears in a catalog or sales quotation.

RFQ Data Maturity Levels

Completed Knife Gate Valve Specification Example

The following example demonstrates how buyer inputs, manufacturer outputs and open items can be separated. It is a field-structure example only and must not be copied directly as an approved specification for another project.

Example Project and Service Inputs

The example is a replacement isolation valve in an abrasive slurry line. The project team knows the pipe size and basic process duty, but some differential-pressure and material details remain open.

Example Manufacturer-Confirmed Outputs

The manufacturer would use the submitted service information to propose a valve design, seat arrangement, component materials and actuator.

The proposal should be recorded in the technical offer rather than inserted into the RFQ as an unverified assumption.

Open Items Marked as TBD or Manufacturer to Confirm

This format prevents unresolved project inputs from being confused with manufacturer-confirmed product data. Every TBD item that can affect fit, shutoff, actuation or material suitability should be closed before final approval or recorded as an accepted deviation. Use the final review below to check the same responsibilities against the actual project RFQ.

Final Knife Gate Valve RFQ Review Before Quotation or Order Release

The final review should answer three separate questions:

1. Is the service described accurately?
2. Does the proposed product comply with that service?
3. Are the dimensions, documents and open items controlled?

Technical Completeness Check

Confirm that the RFQ or technical clarification includes:

• media and solids data;
• particle and fibrous conditions;
• pressure and temperature;
• differential and reverse-pressure conditions;
• valve duty and cycle rate;
• pressure direction and shutoff requirement;
• connection and drilling;
• component material requirements;
• actuation and control data;
• installation and access constraints.

An incomplete field does not always prevent a budget quotation, but it should remain marked as open rather than being replaced by an invisible assumption.

Product and Document Cross-Check

Review the datasheet and drawing against the RFQ:

• proposed design matches the stated service;
• size and connection match the pipeline;
• product rating covers the project condition;
• directional capability matches the piping arrangement;
• component materials are listed;
• actuator is confirmed for the required duty;
• envelope fits the available space;
• required documents and tests are included;
• deviations are clearly stated;
• drawing and datasheet revisions agree.

Questions to Resolve Before Final Approval

Do not release the valve for final manufacture or installation while fit-critical questions remain unresolved.

Unresolved differential pressure, reverse pressure, connection, clearance or fail-position requirements may create conflicts during drawing approval, installation or commissioning—even when the quoted valve appears generally suitable.

Typical open items include:

• unknown maximum differential pressure;
• uncertain reverse-pressure condition;
• incomplete chemical composition;
• unspecified fail position;
• unconfirmed flange drilling;
• insufficient actuator clearance;
• preliminary rather than certified dimensions;
• missing control diagrams;
• material certificates not included in scope;
• vendor deviations not accepted.

Final RFQ Completeness Check

Recurring omissions in pressure direction, differential pressure, actuator duty and installation data are engineering selection risks, not merely missing administrative fields. They should be resolved before approval rather than left for site installation.

FAQ

What information is required to specify a knife gate valve?

At minimum, provide the media, solids condition, size, operating and differential pressure, temperature, valve duty, pressure direction, connection, actuation method and required documents. A detailed engineering RFQ should also include particle characteristics, material restrictions, installation constraints, control accessories and testing requirements.

Can I request a quote without a complete datasheet?

Yes. A preliminary quotation can often be prepared from minimum process and pipeline data. All assumptions and missing fields should be identified, and the final configuration should not be approved until the manufacturer’s datasheet and drawings have been reviewed.

What is the difference between a specification and a datasheet?

The specification defines what the project requires. The manufacturer’s datasheet records the product configuration proposed to meet those requirements, including the model, rating, materials, actuator and dimensions. Confusing the two can lead a buyer to order from generic product data without confirming whether the offered configuration matches the actual service.

Is a datasheet enough for final valve selection?

A datasheet alone is usually not sufficient for final project approval. It can confirm the technical configuration, but installation envelope, connection details and maintenance clearance should be checked on the GA or certified drawing. Orientation, support and operating requirements should also be reviewed against the IOM and project piping arrangement.

Should line pressure or differential pressure be specified?

Both may be relevant. Line pressure describes the process pressure, while differential pressure describes the pressure difference acting across the gate. Differential pressure is particularly important for shutoff-load and actuator review and should not be replaced by the normal line-pressure value.

Does flow direction matter in a knife gate valve RFQ?

Yes. The RFQ should identify the normal pressure direction, upstream side and any reverse-pressure requirement. The manufacturer should then confirm seat orientation and whether the proposed design is intended for one-direction or two-direction shutoff.

What actuator information should be included?

State the operating method, available utility, cycle frequency, required opening or closing time, fail position, environmental conditions and required accessories. The manufacturer should confirm the final actuator model, sizing basis and control arrangement.

Which drawings and certificates should be requested?

For configuration confirmation, request the technical offer and project datasheet. For installation and interface review, request the GA or certified drawing. Material certificates and test reports provide material and quality evidence, while the IOM provides installation, operation and maintenance instructions. Automated valves may also require actuator, wiring or pneumatic documentation.

Conclusion

A reliable knife gate valve specification begins with the service conditions, not with a product model.

The buyer defines the media, solids, particle conditions, pressure, temperature, duty, direction, interface, actuation and project-document requirements. The manufacturer then confirms the suitable valve design, component materials, seat arrangement, actuator, rating and dimensions.

Separating project inputs from manufacturer outputs makes offers easier to compare and keeps assumptions visible. Before order release, the datasheet, drawing, deviations, document scope and fit-critical open items should be reviewed as one controlled technical package.

Application / Specification Support

NTGD can support the review of an existing knife gate valve specification, datasheet or GA drawing, or help organize missing RFQ data before a technical quotation. Useful inputs include the process media, solids and particle conditions, pressure, temperature, size, connection, operating frequency, actuation requirements and available installation information.