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[Audio] QA/QC -203 Statistical Quality Control Part 1 Unit 11: 1 37 Pg:.

[Audio] U-11Statistical Quality Control Part 1 Objectives  Understand the concept of statistical quality control  Identify the types of statistical quality control  Understanding and Applying Quality Control Methods ( Flow Chart , Check List , Cause and Effects Diagram , Acceptance Sampling ) in Construction ..

[Audio] U-11Statistical Quality Control Part 1 Definition and Importance of S-Q-C in Construction Statistical Quality Control (S-Q-C--) is a methodology that applies statistical methods to monitor and control the quality of processes in construction projects. It ensures that construction processes meet predetermined quality standards by identifying variations in construction processes and materials early, thus reducing errors, defects, and rework. S-Q-C is critical in construction because it provides a data-driven approach to quality management, enabling decision-makers to monitor project performance quantitatively, predict potential issues, and take corrective action before defects occur..

[Audio] U-11Statistical Quality Control Part 1 Key Elements of S-Q-C in Construction Variation and its Sources: Variations in materials, workmanship, environmental conditions, and equipment can all lead to quality issues. Control Limits and Specifications: Define acceptable ranges for performance parameters such as concrete strength, steel elasticity, or surface flatness in road construction. Continuous Monitoring: Ongoing inspections and statistical testing help keep the project within defined quality limits..

[Audio] U-11Statistical Quality Control Part 1 Types of Statistical Quality Control  Descriptive Statistics in Construction Descriptive statistics summarize large sets of data, such as averages (mean), standard deviation, and range. For instance, monitoring concrete strength samples over a week and calculating their mean and standard deviation helps in understanding material consistency.  Statistical Process Control (S-P-C--) S-P-C tools such as control charts and run charts help monitor process performance over time. This ensures that the construction process remains within control limits. A common example is using S-P-C to monitor the curing time and compressive strength of concrete over time..

[Audio] U-11Statistical Quality Control Part 1 Developing Statistical Quality Control Plans  Steps to Implementing an S-Q-C Plan Define Quality Standards: Set standards for each construction phase (for example, acceptable tolerances for concrete strength, steel reinforcement positioning). Identify Critical Control Points: Identify areas most susceptible to defects (for example, concrete mixing, steel welding). Establish Control Procedures: Create a procedure for regular sampling, testing, and control charting..

[Audio] U-11Statistical Quality Control Part 1 Types of Statistical Quality Control  Acceptance sampling in Construction Acceptance sampling involves testing a subset of materials (like steel bars or asphalt) and making decisions about accepting or rejecting the entire batch based on the sample results. This reduces the need for 100% testing, making QC more efficient..

[Audio] U-11Statistical Quality Control Part 1 Statistical Quality Control in Construction  Methods of Statistical Quality Control (S-Q-C--) in Construction Statistical Quality Control (S-Q-C--) utilizes various statistical methods to measure, monitor, and control the quality of processes in construction projects. These methods ensure that construction practices meet desired standards and that variations in processes are detected and corrected early to minimize defects. Below, we explore the major S-Q-C methods used in construction projects:.

[Audio] U-11Statistical Quality Control Part 1 Flow Charts in Quality Control A flow chart is a graphical representation of a process or system, illustrating the sequence of steps required to complete a task. In construction quality control, flow charts help visualize the workflow for completing tasks, ensuring all steps are followed in a logical, consistent manner. Application in Construction Projects: Process Mapping: Flow charts help map the workflow for construction tasks such as concrete pouring, formwork inspection, or equipment installation. By showing the sequence of operations, they ensure that all necessary steps are followed..

[Audio] U-11Statistical Quality Control Part 1 Flow Charts in Quality Control Quality Assurance Procedures: Flow charts can be used to visualize how a quality assurance process works, ensuring that materials and workmanship meet specified standards. Problem Identification: Flow charts are useful for tracing the root cause of a quality issue by visualizing where a deviation from standard procedures might have occurred..

[Audio] U-11Statistical Quality Control Part 1 Components of a Flow Chart Start/End (Terminator): Represents the beginning or end of a process. Process (Task): A box that shows a specific task or activity that needs to be performed. Decision: A diamond shape representing a point where a decision must be made (for example, "Is the material acceptable?"). Flow Line: Arrows that show the direction of the workflow. Input/Output: Parallelogram shapes that indicate material inputs or process outputs..

[Audio] U-11Statistical Quality Control Part 1 Benefits of Flow Charts: Clarity: Provides a clear, visual roadmap for completing tasks, helping to avoid confusion or missed steps. Process Optimization: Identifies inefficiencies or bottlenecks in the workflow, enabling teams to optimize the process. Standardization: Ensures that every team follows the same process, maintaining consistency across different projects or phases. Training Tool: Flow charts serve as a training tool for new employees, helping them understand each step of the quality control process..

[Audio] U-11Statistical Quality Control Part 1 Flow Chart in Construction.

Flow Chart in Construction U-11Statistical Quality Control Part 1.

[Audio] U-11Statistical Quality Control Part 1 Example (1) Flow Chart in Construction Scenario : During a large commercial building project, Using the this activities to prepare flow chart for the concrete pouring : Ready for Concrete: Check that the site is prepared, forms are in place, and reinforcements are correctly positioned. Concrete Mix Design: Verify that the mix design complies with specifications before proceeding with the pour. Adjust Mix Ratio: If the mix doesn't meet the specifications, adjustments are made, and the mix is re-tested..

[Audio] U-11Statistical Quality Control Part 1 Example (1) Flow chart in Construction Monitor Slump/Temperature: During pouring, check the concrete slump (workability) and temperature to ensure they meet the project specifications. Curing Process: Begin the curing process after pouring to ensure that the concrete gains strength according to the specified time..

[Audio] U-11Statistical Quality Control Part 1 Check lists in Quality Control A checklist is a systematic tool used in construction quality control to ensure that all activities, materials, and procedures comply with predefined standards and specifications. Checklists provide a step-by-step framework to verify that specific tasks are completed and meet quality requirements. Application in Construction Projects: Pre-Construction Checklists: Ensures that all preparatory work, such as obtaining permits, approving design drawings, and confirming material orders, is complete before the project begins..

[Audio] U-11Statistical Quality Control Part 1 Check lists in Quality Control On-Site Inspection Checklists: Helps site engineers and inspectors verify that materials and workmanship on-site meet quality standards, ensuring all essential quality checks are followed in various stages of construction. Final Inspection Checklists: Ensures that completed construction work is in accordance with contract specifications and that all defects are rectified before handing the project over to the client..

[Audio] U-11Statistical Quality Control Part 1 Common Types of Checklists  Material Checklists: Verifies that materials delivered to the construction site meet quality standards. For instance, the checklist may include parameters like the correct grade of steel bars or ensuring cement complies with specified standards. Example: A checklist for concrete batching might include items like ensuring the correct watercement ratio, appropriate aggregate size, and mixing time..

[Audio] U-11Statistical Quality Control Part 1  Workmanship Checklists: Focuses on the quality of work performed by laborers. For example, a checklist for brickwork will include checks for mortar mix, brick alignment, and joint thickness. Example: During roof installation, a checklist could verify that waterproofing materials are correctly applied, and that all joints and flashings are sealed properly..

[Audio] U-11Statistical Quality Control Part 1 Common Types of Checklists  Safety Checklists: Ensure safety standards are adhered to on-site to protect workers and prevent accidents. Example: A checklist for scaffolding might include ensuring proper erection, securing, and stability of scaffolding structures before workers use them..

[Audio] U-11Statistical Quality Control Part 1 Benefits of Checklists Consistency: Standardizes quality control across different teams and shifts by providing a structured format for inspections. Error Prevention: Reduces the likelihood of missing critical steps or tasks in a process. Accountability: Documents the completion and inspection of work, helping track who was responsible for each task. Compliance: Ensures that all work complies with legal and contract requirements..

[Audio] U-11Statistical Quality Control Part 1 Checklists in Construction Checklist /Item Description Status Comments 1. Excavation Completed Excavation depth: 1.5 meters Ensure excavation is done according to the approved drawings and safety measures are in place. 2. Concrete Mix Verify water-cement ratio and ensure aggregates are clean and within specified limits. In-Progress Pending lab test results 3. Reinforcement Check placement, spacing, and cover of steel reinforcement as per the design. Completed Satisfactory 4. Curing Ensure proper curing practices are followed for concrete work for 7 to 14 days. Not Started Starts on 1st October 5. Safety Gear Workers wearing safety helmets, gloves, and boots. Completed Inspection by Safety Officer.

[Audio] U-11Statistical Quality Control Part 1 Example (2) Checklists in Construction Scenario : During a large commercial building project, the quality of the concrete being poured is critical to ensuring the structural integrity of the building. A checklist is used before each concrete pour to verify that all required preconditions have been met. Checklist: Concrete Grade Verified: Confirm the concrete mix is the specified grade (for example, M25). Reinforcement Placed: Check if steel reinforcements are correctly installed as per design drawings. Formwork Setup: Ensure formwork is stable and leak-proof. Slump Test Performed: Verify the workability of the concrete mix with a slump test..

[Audio] U-11Statistical Quality Control Part 1 Example (2) Checklists in Construction Weather Conditions: Ensure the weather is conducive for concrete pouring (for example, temperature not too hot or cold). Vibration of Concrete: Ensure that vibrating equipment is ready for removing air pockets during pouring. Outcome: The checklist ensures all conditions are met before pouring begins, preventing potential defects such as honeycombing or improper curing..

[Audio] U-11Statistical Quality Control Part 1 Cause-and-Effect (Ishikawa) Diagrams Also known as fishbone diagrams, cause-and-effect diagrams are used to systematically identify the root causes of quality problems in construction processes. These diagrams help visualize the different factors that contribute to quality issues. Application in Construction: Identifying Causes of Defects: For example, if cracks appear in a concrete foundation, a cause-andeffect diagram can help explore factors like material quality, environmental conditions, workmanship, and equipment..

[Audio] U-11Statistical Quality Control Part 1 Cause-and-Effect (Ishikawa) Diagrams Steps for Creating a Cause-and-Effect Diagram: Define the Problem: State the problem (for example, cracks in a wall). Identify Major Categories: Major causes may include materials, methods, manpower, machines, and environment. Brainstorm Sub-Causes: List specific factors under each category (for example, under "Materials," list improper concrete mix or contaminated water). Analyze the Diagram: Review the diagram to determine which factors contribute most to the problem..

[Audio] U-11Statistical Quality Control Part 1 Cause and Effects Diagram in Construction.

[Audio] U-11Statistical Quality Control Part 1 Example (3) Cause and Effect Diagram in Construction Scenario: Cracking and Low Strength in Poured Concrete for a Building Foundation Problem (Effect): After pouring the concrete for a building foundation, multiple cracks appeared, and the compressive strength tests revealed that the concrete did not meet the required design strength. The contractor and consultant are concerned about the structural integrity of the foundation and must investigate the root causes of the issue. Major Categories of Causes: Materials Labor Equipment Methods Environment Management.

[Audio] U-11Statistical Quality Control Part 1 Acceptance Sampling Acceptance sampling is a method where a random sample from a batch of materials is inspected to decide whether the entire batch meets the required quality standards. It is often used for construction materials like concrete, steel, or asphalt. Types of Acceptance Sampling Plans: Single Sampling Plan: Process: A single random sample is taken from the batch. Based on the inspection results, the batch is either accepted or rejected..

[Audio] U-11Statistical Quality Control Part 1 Acceptance Sampling Application: Testing concrete strength by randomly sampling cubes from a batch. If the sample passes the strength test, the whole batch is accepted. Double Sampling Plan: Process: Two samples are taken. If the first sample results are inconclusive (borderline between acceptance and rejection), a second sample is taken before making a final decision. Application: Testing steel bar strength. If the first sample yields marginal results, a second sample is tested before deciding to accept or reject the batch..

[Audio] U-11Statistical Quality Control Part 1 Example(4) Acceptance Sampling for Concrete Strength Testing Scenario: A construction project involves pouring large quantities of concrete for the foundation of a multi-story building. The contract requires that the compressive strength of the concrete must meet or exceed 30 MPa (mega Pascal's) after 28 days of curing. To ensure the quality of the concrete being used, acceptance sampling is applied to test whether the concrete meets the required strength. Process of Acceptance Sampling: Concrete Batch Selection: 1. Each concrete batch delivered to the site consists of a certain volume (for example, 100 cubic meters). 2. The contractor or quality control team cannot test the entire batch for strength, so they take random.

[Audio] U-11Statistical Quality Control Part 1 Example (4): Acceptance Sampling for Concrete Strength Testing 3. samples of fresh concrete from each batch during the pouring process. Sample Size: 1. The quality control plan specifies that for every 100 cubic meters of concrete, 5 samples will be taken at random intervals. 2. These samples are formed into test cylinders and cured under controlled conditions. Testing the Samples: 1. After 28 days, the 5 concrete cylinders are tested for compressive strength using a compression testing machine. 2. The results from the samples are compared to the required strength of 30 MPa..

[Audio] U-11Statistical Quality Control Part 1 Example(4): Acceptance Sampling for Concrete Strength Testing Acceptance Criteria: 1. The acceptance sampling plan is set up with certain criteria: 2. If all of the 5 samples meet or exceed the strength requirement of 30 MPa, the entire batch is accepted. 3. If 1 or 2 samples fall slightly below 30 MPa but within an acceptable range (for example, 28-30 MPa), additional tests may be conducted to determine whether the batch can still be accepted. 4. If 3 or more samples fall below 30 MPa, or any sample is significantly below the acceptable range (for example, less than 28 MPa), the entire batch is rejected..

[Audio] U-11Statistical Quality Control Part 1 Example (4): Acceptance Sampling for Concrete Strength Testing Decision: 1. If the batch is accepted, the project continues with the assumption that the concrete quality is adequate. 2. If the batch is rejected, the contractor may need to remove the defective concrete or perform remedial actions, such as reinforcing the structure, depending on the severity of the failure..

[Audio] U-11Statistical Quality Control Part 1 Summary  Statistical Quality Control (S-Q-C--) is a methodology that applies statistical methods to monitor and control the quality of processes in construction projects. It ensures that construction processes meet predetermined quality standards by identifying variations in construction processes and materials early, thus reducing errors, defects, and rework.  A flow chart is a graphical representation of a process or system, illustrating the sequence of steps required to complete a task. In construction quality control, flow charts help visualize the workflow for completing tasks, ensuring all steps are followed in a logical, consistent manner..

[Audio] U-11Statistical Quality Control Part 1 Summary  A checklist is a systematic tool used in construction quality control to ensure that all activities, materials, and procedures comply with predefined standards and specifications. Checklists provide a step-by-step framework to verify that specific tasks are completed and meet quality requirements.  cause-and-effect diagrams are used to systematically identify the root causes of quality problems in construction processes.  Acceptance sampling is a method where a random sample from a batch of materials is inspected to decide whether the entire batch meets the required quality standards. It is often used for construction materials like concrete, steel, or asphalt..