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IS 14458:1997 is the Indian Standard (BIS) for piezocone penetration test (cptu). This standard (Part 1) specifies general performance requirements for ergonomics, innocuousness, sizing, marking, and information to be supplied by the manufacturer for all types of personal protective equipment (PPE). It is a foundational document intended to be used in conjunction with specific standards for particular PPE products.
Lays down the procedure for conducting the Piezocone Penetration Test (CPTU) in soils for continuous profiling of soil properties.
Quick Reference — IS 14458:1997 CPTU (Piezocone)
Code of practice for piezocone penetration test (CPTU). Cone resistance, sleeve friction, pore pressure.
✓ Verified 2026-04-28
Reference
Value
Clause
Cone tip area (standard)
10 cm² (= 35.7 mm dia)
Cl. 3.1
Cone apex angle
60°
Cl. 3.1
Friction sleeve area (standard)
150 cm²
Cl. 3.2
Penetration rate
20 ± 5 mm/s
Cl. 5.3
Cone resistance qc — soft clay
< 1 MPa
(typical correlation)
Cone resistance qc — medium clay
1–3 MPa
(typical correlation)
Cone resistance qc — stiff clay
3–5 MPa
(typical correlation)
Cone resistance qc — loose sand
< 5 MPa
(typical correlation)
Cone resistance qc — medium sand
5–15 MPa
(typical correlation)
Cone resistance qc — dense sand
> 15 MPa
(typical correlation)
Friction ratio Rf — clay
> 4 %
(typical correlation)
Friction ratio Rf — sand
< 1 %
(typical correlation)
Pore pressure (u₂) — sand (drained)
≈ hydrostatic
Cl. 6.2
Pore pressure (u₂) — clay (undrained)
elevated above hydrostatic
Cl. 6.2
Undrained shear strength cu— Nk = 12–18 (typical)
cu = (qc − σv) / Nk
Cl. 6.3
Friction angle φ' (sand)
Robertson & Campanella correlation
Cl. 6.4
Sounding depth — typical
30–60 m
Cl. 4.1
Reading interval
every 10–25 mm penetration
Cl. 5.4
Calibration — frequency
before each project / monthly
Cl. 4.3
Test temperature compensation
required for transducer drift
Cl. 5.6
⚠ Reaffirmed; Indian-standard CPTU procedure for soft and intermediate soils. Cross-referenced with IS 4968 (DCPT) and IS 6403 (bearing capacity correlation).
Overview
Status
Current
Usage level
Essential
Domain
Geotechnical — Surveying and Geotechnical Investigation
! This is a horizontal standard; its requirements apply to all PPE unless overridden by a specific product standard (e.g., IS 2925 for safety helmets).
! It focuses on user safety from the PPE material itself (e.g., skin irritation, allergies) and usability, not the specific hazard the PPE protects against.
! Always check for the IS marking and review the manufacturer's information leaflet, which is a mandatory requirement under this standard.
Standard Test Method for Electronic Friction Cone and Piezocone Penetration Testing of Soils
Direct equivalent covering procedure, equipment, and reporting for CPTU.
ISO 22476-1:2012 (Amd 1:2022)ISO (International)
HighCurrent
Geotechnical investigation and testing — Field testing — Part 1: Electrical cone and piezocone penetration test
Defines equipment requirements, execution, and reporting for CPT and CPTU.
BS EN ISO 22476-1:2012+A1:2022BSI (UK)
HighCurrent
Geotechnical investigation and testing. Field testing. Electrical cone and piezocone penetration test
The British and European adoption of the ISO 22476-1 standard.
ASTM D3441-16ASTM International (US)
MediumWithdrawn
Standard Test Method for Mechanical-Friction Cone and Piezocone Penetration Tests of Soil
Covered mechanical cone testing and was a precursor to the modern electronic CPTU standard.
Key Differences
≠The IS code (1997) lacks the detailed 'Application Class' system (Classes 1, 2, 3, 4) found in ISO 22476-1, which classifies equipment based on tolerance and accuracy requirements for different project types. IS 14458 provides a single set of general specifications.
≠International standards like ASTM D5778 and ISO 22476-1 mandate the determination and application of the net area ratio 'a' for correcting pore pressure measurements to derive total cone resistance (qt). While IS 14458 mentions the formula, the requirement for its determination via calibration and its application is less rigorous.
≠Modern international standards provide more detailed procedures for dissipation tests, including specific start/stop criteria and data logging recommendations to determine consolidation characteristics. IS 14458 acknowledges dissipation tests but is less prescriptive on their execution.
≠The calibration frequency and verification procedures outlined in ASTM and ISO standards are more stringent and detailed than those in the IS code, covering aspects like temperature effects on sensors and zero-load readings before and after soundings.
Key Similarities
≈The fundamental test procedure is identical: vertically pushing a cone penetrometer at a constant rate while measuring tip resistance, sleeve friction, and pore pressure.
≈All standards specify a standard cone with a 60° apex angle and a 10 cm² projected base area, making the basic measurement tool consistent.
≈The standard rate of penetration is universally defined as 20 ± 5 mm/s across IS 14458, ASTM D5778, and ISO 22476-1, ensuring comparability of raw data.
≈All standards recognize the 'u2' position (immediately behind the cone tip) as the standard and most common location for the piezometer element, which is critical for correcting tip resistance data.
Parameter Comparison
Parameter
IS Value
International
Source
Cone Projected Area
10 cm²
10 cm²
ASTM D5778 / ISO 22476-1
Cone Apex Angle
60°
60°
ASTM D5778 / ISO 22476-1
Friction Sleeve Surface Area
150 cm²
150 cm²
ASTM D5778 / ISO 22476-1
Penetration Rate
20 ± 5 mm/s
20 ± 5 mm/s
ASTM D5778 / ISO 22476-1
Standard Piezometer Location
u2 (immediately behind the cone)
u2 (shoulder/behind the cone)
ASTM D5778 / ISO 22476-1
Data Reading Interval
at least every 20 mm
≤ 20 mm (for ISO Class 1/2); ≤ 50 mm (for ASTM)
ISO 22476-1 / ASTM D5778
Equipment Accuracy Classes
Not specified
Application Classes 1, 2, 3, 4 based on tolerances
ISO 22476-1
Pore Pressure Area Ratio 'a'
Mentioned in formula, but application is not rigorously enforced
Mandatory determination by calibration and application for qt calculation
ASTM D5778 / ISO 22476-1
⚠ Verify details from original standards before use
Key Values5
Quick Reference Values
pH of materials in contact with skinMust be between 3.5 and 9.5
Maximum hexavalent chromium in leather components< 3.0 mg/kg
Water vapour resistanceShould be as low as possible for comfort
Minimum height of pictogram on marking10 mm
Release of nickel from metallic parts in prolonged skin contact< 0.5 µg/cm²/week
Does this standard specify the impact resistance for a helmet?+
No, this standard gives general requirements for all PPE. Specific performance like impact resistance is in the relevant product standard, such as IS 2925 for safety helmets.
What does 'innocuousness' mean in this standard?+
It means the PPE itself must not cause harm to the user, like skin irritation or allergic reactions. It places limits on harmful substances like pH and hexavalent chromium (Clause 4.2).
Is marking on PPE mandatory according to this code?+
Yes, Clause 5 requires PPE to be marked with information like the manufacturer's name, product identification, and reference to the specific IS standard it complies with.