What is Technical Bid Evaluation (TBE)?

TBE is the systematic process of evaluating vendor proposals against technical requirements. For pumps, it assesses performance compliance, materials, quality, operating costs, and vendor capability.

What are the most critical evaluation criteria for pumps?

Critical pass/fail items: NPSH margin (≥1.0m or 30% NPSHr), operating point within 80-110% BEP, materials compliance. Key scoring items: efficiency, proven design, delivery, warranty.

How do I compare pumps with different efficiencies?

Calculate annual energy cost: Annual Cost = (Power × Hours × Rate) / Efficiency. A 3% efficiency difference on a 100 kW pump running 8000 hrs at $0.10/kWh = $24,000/year savings.

Should I always choose the cheapest pump?

No. Energy cost over 20-year pump life typically exceeds initial cost by 10-20×. Always perform Life Cycle Cost (LCC) analysis comparing initial + energy + maintenance costs.

How to Evaluate Centrifugal Pump Vendor Quotations

1. TBE Process Overview

1.1 Evaluation Phases

Vendor Quotations Received
         │
         ▼
┌─────────────────────────────┐
│ Phase 1: Administrative     │  Pass/Fail
│  - Document completeness    │
│  - AVL compliance           │
└─────────────────────────────┘
         │
         ▼
┌─────────────────────────────┐
│ Phase 2: Technical Pass/Fail│  Mandatory Requirements
│  - NPSH compliance          │
│  - Performance tolerances   │
│  - Material compliance      │
└─────────────────────────────┘
         │
         ▼
┌─────────────────────────────┐
│ Phase 3: Technical Scoring  │  Weighted Evaluation
│  - Efficiency               │
│  - BEP proximity            │
│  - Proven design            │
└─────────────────────────────┘
         │
         ▼
┌─────────────────────────────┐
│ Phase 4: Commercial Review  │  Cost Analysis
│  - Life cycle cost          │
│  - Delivery schedule        │
│  - Warranty terms           │
└─────────────────────────────┘
         │
         ▼
    Recommendation

1.2 Evaluation Team Responsibilities

Role	Responsibilities
Lead Engineer	Overall evaluation coordination, final recommendation
Process Engineer	Performance verification, NPSH compliance
Mechanical Engineer	Materials, seal, bearing requirements
Procurement	Commercial evaluation, schedule

2. Phase 1: Administrative Review (Pass/Fail)

2.1 Document Completeness Checklist

Document	Required	Received	Status
Completed datasheet (all sections)	✓
Performance curve (H-Q, η, P)	✓
NPSH curve	✓
General arrangement drawing	✓
Cross-section drawing	✓
Bill of materials	✓
Deviation/exception list	✓
Reference list (similar service)	✓
QA/QC plan outline	✓
Delivery schedule	✓
Commercial quotation	✓

Action: Incomplete quotations → Request missing documents before proceeding

2.2 AVL Compliance

Check Item	Vendor A	Vendor B	Vendor C
On Approved Vendor List (AVL)
Manufacturing location approved
Sub-vendors identified
Quality system certification (ISO 9001)

Action: Non-AVL vendor → Requires management exception approval

3. Phase 2: Technical Pass/Fail Review

3.1 NPSH Compliance (Critical)

Calculation:

NPSH Margin = NPSHa (specified) - NPSHr (offered)

Required Margin per API 610:
  NPSH Margin ≥ MAX(1.0 m, 0.3 × NPSHr)

Vendor	NPSHa (specified)	NPSHr (offered)	Margin
A	m	m	m
B	m	m	m
C	m	m	m

Criteria:

Margin	Action
≥ API 610 requirement	PASS
0.5m to requirement	CONDITIONAL - Request clarification
< 0.5m	FAIL - Reject quotation

3.2 Performance Tolerances (API 610 Table 18)

Parameter	Tolerance	Vendor A	Vendor B	Vendor C
Head at rated flow	±3%
Flow at rated head	±3%
NPSHr at rated flow	≤ guaranteed
Efficiency at rated	≥ guaranteed OR ≤ 5% below
Power at rated	≤ 104% of guaranteed

Verification:

Example:
  Specified Head = 80 m
  Tolerance = ±3% = ±2.4 m
  Acceptable range = 77.6 to 82.4 m

  Vendor offers 79.5 m → PASS (within tolerance)

3.3 BEP Operating Point Check

Calculation:

BEP Ratio = (Rated Flow / BEP Flow) × 100%

Vendor	Rated Flow	BEP Flow	BEP Ratio
A	m³/h	m³/h	%
B	m³/h	m³/h	%
C	m³/h	m³/h	%

Criteria (API 610):

BEP Ratio	Status	Notes
80-110%	PASS - Preferred operating region	Best reliability
70-80% or 110-120%	CONDITIONAL - Allowable region	Reduced life expected
<70% or >120%	FAIL - Outside allowable	Reject quotation

3.4 Materials Compliance

Component	Specified Class/Material	Vendor A	Vendor B	Vendor C
Casing
Impeller
Shaft
Wear rings
Seal faces
Seal elastomers
Bearings

Material Equivalents:

If Specified	Acceptable Alternatives
S-1 (Carbon Steel)	ASTM A216 WCB, WCC
S-4 (316 SS)	CF8M, 316L
S-5 (Duplex)	CD4MCuN, UNS S31803

3.5 Mechanical Requirements

Requirement	Specification	Vendor A	Vendor B	Vendor C
Pump type
Bearing life (L10)	≥25,000 hrs
Vibration limit	≤3.0 mm/s
Seal type (API 682)
Seal flush plan
Driver power margin	≥10%

4. Phase 3: Technical Scoring

4.1 Scoring Criteria

Score	Definition
5	Exceeds requirement significantly
4	Fully meets requirement
3	Acceptable with minor deviation
2	Marginal - requires clarification
1	Below requirement
0	Does not meet / Not acceptable

4.2 Weighted Evaluation Matrix

Category	Criteria	Weight
Technical (70%)
	BEP proximity	15%
	Efficiency at rated	20%
	NPSH margin	10%
	Materials compliance	10%
	Proven design/references	10%
	Mechanical design	5%
Commercial (30%)
	Price	15%
	Delivery	10%
	Warranty	5%
Weighted Total		100%

4.3 Efficiency Comparison

Single Point Comparison:

Efficiency Score = (Vendor Efficiency / Best Efficiency) × 5

Example:
  Vendor A: 78%, Vendor B: 75%, Vendor C: 72%
  Best = 78%

  Vendor A score = (78/78) × 5 = 5.0
  Vendor B score = (75/78) × 5 = 4.8
  Vendor C score = (72/78) × 5 = 4.6

Multiple Operating Points - Power Consumption Indicator (PCI):

PCI = Σ (Hydraulic Power × % Operating Time / Efficiency)

Lower PCI = Lower operating cost = Better

Point	Head	% Time	Vendor A η	Vendor B η
Rated	m	%	%	%
Normal	m	%	%	%
Minimum	m	%	%	%

PCI Calculation:

Vendor A PCI = (HP₁×T₁/η₁) + (HP₂×T₂/η₂) + (HP₃×T₃/η₃) = ____
Vendor B PCI = (HP₁×T₁/η₁) + (HP₂×T₂/η₂) + (HP₃×T₃/η₃) = ____

PCI Score = (Lowest PCI / Vendor PCI) × 5

5. Phase 4: Commercial Evaluation

5.1 Life Cycle Cost (LCC) Analysis

Formula:

LCC = Initial Cost + Energy Cost + Maintenance Cost

Energy Cost (20 yr) = (Power × Hours × Rate × 20) / Efficiency

Example:

Parameter	Vendor A	Vendor B
Initial pump cost	$50,000	$45,000
Motor cost	$15,000	$15,000
Total Initial	$65,000	$60,000

Rated power	100 kW	105 kW
Efficiency	78%	74%
Shaft power	128 kW	142 kW

Operating hours	8,000 hr/yr	8,000 hr/yr
Electricity rate	$0.10/kWh	$0.10/kWh
Annual energy cost	$102,400	$113,600
20-year energy	$2,048,000	$2,272,000

Maintenance (20 yr)	$100,000	$100,000

Total LCC	$2,213,000	$2,432,000
LCC Savings	$219,000	-

Result: Vendor A saves $219,000 over 20 years despite $5,000 higher initial cost.

5.2 Delivery and Schedule

Milestone	Required	Vendor A	Vendor B	Vendor C
Ex-works delivery	weeks
FAT (if required)	weeks
Documentation	weeks
Spares delivery	weeks

5.3 Warranty Comparison

Warranty Term	Vendor A	Vendor B	Vendor C
Period (months)
Coverage
Exclusions
Extension available

6. Deviation Analysis

6.1 Deviation Categories

Category	Definition	Action
Major	Affects safety, performance, or code compliance	Reject or require redesign
Minor	Affects quality but can be mitigated	Accept with conditions
Editorial	Clarification only, no technical impact	Accept

6.2 Deviation Evaluation Form

#	Description	Category	Risk	Vendor Response	Evaluator Decision
1
2
3

6.3 Common Deviations and Typical Resolutions

Deviation	Risk	Typical Resolution
Different pump type (OH1 vs OH2)	High	Usually reject for hot service
Alternative material class	Medium	Accept if equivalent per API 610
Smaller/larger impeller	Medium	Verify within allowable range
Different seal flush plan	Medium	Review with seal vendor
Extended delivery	Low	Commercial negotiation
Alternative coupling	Low	Accept if equivalent standard

7. Red Flags and Warning Signs

7.1 Performance Red Flags

Red Flag	Why It’s Concerning	Action
BEP ratio >115%	High vibration, short bearing life	Reject or request redesign
BEP ratio <75%	Recirculation damage, cavitation	Reject or request redesign
Impeller at max diameter	No head increase capability	Request confirmation of margin
Impeller at min diameter	Poor efficiency, limited future	Request confirmation
NPSHr margin <0.5m	High cavitation risk	Reject
Flat H-Q curve	Unstable parallel operation	Request rising curve

7.2 Documentation Red Flags

Red Flag	Possible Issue	Action
Missing performance curve	Unproven design	Request or reject
Generic (not pump-specific) GA	Not engineered for service	Request actual drawing
No reference list	Limited experience	Request or accept with risk
Vague deviation descriptions	Hidden non-compliance	Request clarification
Missing NPSH curve	Cannot verify margin	Request before proceeding

7.3 Commercial Red Flags

Red Flag	Concern	Action
Price significantly below others (>15%)	Cutting corners, errors	Request clarification
Very long delivery	Capacity issues	Verify capability
Excessive exclusions	Hidden costs	Clarify scope
New model without references	Unproven reliability	Consider risk

8. Clarification Questions

8.1 Performance Clarifications

Question	Purpose
Please confirm BEP flow and head for offered pump.	Verify operating region
Please provide efficiency at normal AND rated flow points.	Verify energy consumption
Please confirm NPSHr at rated AND 120% flow.	Verify cavitation margin
What is the minimum continuous stable flow?	Verify recirculation limit
Please confirm impeller diameter as % of maximum.	Verify head margin

8.2 Mechanical Clarifications

Question	Purpose
Please provide L10 bearing life calculation at rated conditions.	Verify 25,000 hr requirement
Please confirm expected vibration level at rated point.	Verify 3.0 mm/s compliance
Please provide seal reference for similar service.	Verify seal reliability
Please confirm motor is non-overloading to end of curve.	Verify motor sizing

9. Evaluation Report Template

9.1 Executive Summary

Project: [Project Name] Equipment: Centrifugal Pump, Tag [P-XXXX] Service: [Service Description] Date: [Evaluation Date]

Quotations Received: X vendors Technically Compliant: X vendors Recommended Vendor: [Vendor Name]

9.2 Summary Comparison Table

Parameter	Specification	Vendor A	Vendor B	Vendor C
Performance
Rated flow (m³/h)
Rated head (m)
NPSHr (m)	≤
Efficiency (%)	≥
BEP ratio (%)	80-110%
Construction
Pump type
Material class
Seal arrangement
Bearing L10 (hrs)	≥25,000
Commercial
Price ($)
Delivery (weeks)
Warranty (months)

9.3 Technical Score Summary

Vendor	Technical Score (70%)	Commercial Score (30%)	Total Score
A
B
C

9.4 Recommendation

Recommended Vendor: [Name]

Technical Justification:

[Key technical advantage 1]
[Key technical advantage 2]

Conditions of Acceptance:

[Condition 1]
[Condition 2]

Required Clarifications:

[Clarification 1]
[Clarification 2]

10. Quick Reference

10.1 Pass/Fail Criteria Summary

Item	Pass	Fail
NPSH margin	≥ MAX(1.0m, 0.3×NPSHr)	< 0.5m
BEP ratio	70-120%	<70% or >120%
Head tolerance	±3% of rated	>±5%
NPSHr	≤ guaranteed	> guaranteed
Materials	Per specification or equivalent	Non-equivalent

10.2 Typical Weightings

Criteria	Typical Weight
Efficiency	15-25%
BEP proximity	10-15%
NPSH margin	10-15%
Materials/construction	10-15%
Proven design	5-15%
Price	10-20%
Delivery	5-10%
Warranty	3-5%