27402 Site Layout Two: Angular and Distance Measurement

NCCER Module 27402: Site Layout Two – Angular and Distance Measurement

Course Information

• Module ID: 27402 (various editions, e.g., 27402-14)
• Training Hours: 37.5 hours (includes classroom instruction, hands-on practice, and review)
• Level: Advanced (typically part of Carpentry Level 4 or standalone Site Layout curriculum)
• Delivery Format: Blended (classroom theory, lab demonstrations, and field practice)
• Prerequisites:
  • Completion of NCCER Site Layout One: Differential Leveling (Module 27401 or equivalent)
  • Basic proficiency in trade mathematics and use of leveling instruments

Course Description

This module covers the principles, equipment, and methods used to perform site layout tasks that require precise angular and distance measurements. Trainees learn to use advanced surveying instruments, apply geometric and trigonometric principles, and execute field tasks such as laying out building lines, establishing perpendiculars, and determining elevations through trigonometric leveling. Emphasis is placed on accuracy, safety, instrument calibration, and practical calculations needed for construction site layout.

Learning Objectives

Upon successful completion of this module, trainees will be able to:

• Identify and apply principles of plane geometry to site layout problems.
• Recognize and mitigate safety hazards associated with layout work and surveying instruments.
• Perform field checks and calibrations to ensure instrument accuracy.
• Describe and use various systems for expressing distance and direction.
• Operate transits, theodolites, electronic distance measurement instruments (EDMIs), and total stations.
• Take accurate horizontal and vertical angular measurements, including direct and reverse readings.
• Perform electronic distance measurements and integrate them with angular data.
• Calculate and convert angular measurements (degrees, minutes, seconds to decimal degrees).
• Apply right-angle trigonometry (sine, cosine, tangent) for layout and elevation calculations.
• Lay out building lines, corners, and offsets using angular methods.
• Determine elevations using trigonometric leveling.
• Conduct basic traverse surveys and check for closure errors.

Competencies/Skills Gained

• Proficiency in identifying plane geometry applications.
• Knowledge of safety protocols for layout and measurement tasks.
• Ability to perform instrument field checks.
• Competence in using layout tools for measurements and building line establishment.
• Skill in calculating, converting, and applying measurements in field scenarios.

Course Outline

The module is divided into key topics, with approximate time allocations:

1. Introduction and Review (5 hours)
   • Overview of site layout tasks requiring angular and distance measurements
   • Review of differential leveling and basic site layout principles
2. Trade Mathematics (7.5 hours)
   • Plane geometry (triangles, polygons, properties)
   • Right-angle trigonometry fundamentals
   • Angular conversions (degrees/minutes/seconds to decimal)
   • Calculation practices for layout problems
3. Safety and Instrument Care (5 hours)
   • Hazards in layout work (e.g., tripods, lasers, traffic)
   • Safe operation and maintenance of instruments
   • Personal protective equipment (PPE) requirements
4. Surveying Instruments and Setup (7.5 hours)
   • Transits, theodolites, EDMIs, and total stations
   • Instrument components, setup, calibration, and care
   • Field checks for accuracy (e.g., peg test, collimation)
5. Angular and Distance Measurement Techniques (7.5 hours)
   • Measuring horizontal and vertical angles
   • Electronic distance measurement methods
   • Integrating angles and distances (e.g., using total stations)
6. Field Applications and Layout Procedures (5 hours)
   • Laying out building lines and perpendiculars
   • Establishing offsets and arcs
   • Trigonometric leveling for elevation determination
   • Basic traverse operations and closure checks

Performance Tasks

Trainees must demonstrate hands-on proficiency under supervision. Typical tasks include:

• Set up and level a theodolite or total station.
• Measure horizontal and vertical angles with acceptable accuracy.
• Perform electronic distance measurements.
• Lay out a rectangular building corner using angular methods.
• Calculate and stake elevations using trigonometric leveling.
• Complete a simple closed traverse and adjust for errors.

Performance is verified by a qualified NCCER evaluator using standardized checklists.

Required Materials

• NCCER Trainee Guide (Module 27402)
• Scientific calculator
• Field notebook and pencils
• Access to surveying equipment: theodolite/total station, tripod, prism/pole, measuring tape
• Safety gear (hard hat, safety glasses, high-visibility vest, gloves)

Assessment and Grading

• Written Exam: Multiple-choice questions covering theory, mathematics, safety, and procedures (70% passing required).
• Performance Evaluation: Hands-on demonstration of key tasks (must achieve proficiency on all required tasks).
• Attendance and Participation: Active engagement in lab and field exercises.
• Certification: Successful completion earns an NCCER module credential, recorded in the National Registry. Contributes toward full craft certification (e.g., Carpentry or Site Layout).

Instructional Methods

• Classroom lectures and discussions
• Multimedia presentations and demonstrations
• Hands-on lab exercises and field practice
• Group problem-solving for calculations
• Review questions and quizzes

This syllabus aligns with NCCER standards and prepares trainees for real-world construction site layout responsibilities. Adjustments may be made based on edition or instructor discretion.