# Presentation: 406684

## Item P-401, Item P-501 Quality Control, Acceptance Criteria, PWL Concepts

- 2006 March FAA Southwest Region Partnership Conference
- Jeff Rapol, Airport Engineering Division, AAS-100
- jeffrey.rapol@faa.gov

## Presentation Objectives

- Clarify the process that ESTIMATES Contractor Production Quality using Lot samples.
- Provide brief explanation of PWL concepts and why there is a degree of uncertainty (risk) associated with acceptance plans when small fractions of material are used to evaluate a day's production. (AC 5370-10 Section 110)

**Southwest Region Partnership Conference****March 2006**

## Quality Control—Hot Mix and PCC

- Responsibility of Contractor
- Contractor controls processes.
- General Provision Section 100 requires a Contractor Quality Control Program when P-401 or P-501 in the project.
- Specification Items P-401 and P-501 contain minimum items to be included in the Contractor Quality Control Program.

**Southwest Region Partnership Conference****March 2006**

## Quality Control—Hot Mix and PCC

- Addresses labs and technicians.
- Processes include lab production, plant production, and field placement.
- Some processes require the Contractor to use statistical quality control measures (run charts and range charts).

**Southwest Region Partnership Conference****March 2006**

## FAA Acceptable Quality

- Item P-401 and Item P-501--FAA assumes process control parameters that are “not unreasonable” for mat density, joint density, air voids, strength, and thickness.
- All acceptance criteria is based on processes with variation in quality conforming to a normal “bell” curve.
- Each day’s production is evaluated and pay is based on daily evaluation of 4 random samples.

**Southwest Region Partnership Conference****March 2006**

## Risk at Acceptable Quality P-401

**98%**

**Risk at Acceptable Quality P-401**

**Southwest Region Partnership Conference****March 2006**

## Risk at Rejectable Quality P-401

**Risk at Rejectable Quality P-401**

**98%**

**Southwest Region Partnership Conference****March 2006**

## Risk at Acceptable Quality P-501

**675 psi**

**Risk at Acceptable Quality P-501**

**Southwest Region Partnership Conference****March 2006**

## Risk at Rejectable Quality P-501

**Risk at Rejectable Quality P-501**

**675 psi**

**Southwest Region Partnership Conference****March 2006**

## FAA Pay Adjustment ScheduleHelps Balance Risk Levels

**FAA Pay Adjustment Schedule****Helps Balance Risk Levels**

**Southwest Region Partnership Conference****March 2006**

## Quality Level “Q” vs. “z”Small Sample Theory

- Quality Level “Q” = _Lot Average - Lower Spec. Limit_					Lot Standard Deviation
- Small Sample Theory:
- At 90 PWL “Q” = 1.200 when sample size, n = 4
- At 90 PWL “Q” = 1.254 when sample size, n = 8
- At 90 PWL “Q” = 1.267 when sample size, n = 16
- At 90 PWL “Q” = 1.275 when sample size, n = 32
- At 90 PWL “Q” = 1.278 when sample size, n = 64
- At 90 PWL “Q” = z = 1.282  when sample size, n = infinity

**Southwest Region Partnership Conference****March 2006**

## PWL Acceptance Limits

- Q = _Lot Average  -  Lower Spec. Limit_	     Lot Standard Deviation
- 4 sublots per LOT:
- At 90 PWL  Q = 1.200  for  n=4
- POPULATION:
- At 90 PWL  Q = z = 1.282  for  n = 

**Southwest Region Partnership Conference****March 2006**

## Item P-401 Acceptance Limits

- z = _Population Average - Lower Spec. Limit_	    Population Standard Deviation
- Stability		_2150 – 1800_ =  1.30  > 1.28		        	       270
- Mat Density  	_98.0 – 96.3_ = 1.32  >  1.28 		                1.3
- Joint Density	_96 – 93.3_ = 1.29  >  1.28			    2.1
- Air Voids		_5 – 4.2_ = 1.23	2._8 – 2_ = 1.23		           0.65			    0.65

**Southwest Region Partnership Conference****March 2006**

## Outlier Check ASTM E 178

-  Outlier Determination for Mat Density.
- Density of four random cores taken from Lot  		 98.9		Average = 97.65	 98.5		Sample s = 1.79	 98.2		n = 4 	 95.0		PWL = 76  (93% lot pay factor)
- Q = _Lot Average  -  Lower Spec. Limit_	     Lot Standard Deviation

**Southwest Region Partnership Conference****March 2006**

## Outlier Check ASTM E 178 

-  Outlier Determination for Mat Density.
- 	E-78 with n=4, 5 percent significance level, critical value for test criterion	= 1.463  Compare
- 	Max  ( 98.9 - 97.65 ) / 1.79 = 0.70 < 1.463 No  Min   ( 97.65 – 95.0 ) / 1.79 = 1.48 > 1.463 Yes

**Southwest Region Partnership Conference****March 2006**

## Outlier Check ASTM E 178

-  Recalculate PWL after eliminating outlier
- Density of 3 random cores taken from Lot A. 98.9	  Average = 98.5398.5	  Sample s = 0.35198.2	  n = 3		  PWL = 100 (106% lot pay factor)
- NOTE:  Outliers exist if:Density greater than (97.65+1.463x1.79), or Density less than  (97.65-1.463x1.79)
- Lot Average +/- Test Criterion*Lot Standard Deviation are Critical Values

**Southwest Region Partnership Conference****March 2006**

## Pay Adjustment Schedule, e.g.Density and Air Voids, Item P-401

**Southwest Region Partnership Conference****March 2006**

## ITEM P- 401 Lot Pay Factor vs.Density Required: Example

**ITEM P- 401 Lot Pay Factor vs.****Density Required: Example**

**Southwest Region Partnership Conference****March 2006**

## P- 401 Lot Pay Factor vs.Air Voids Required: Example

**P- 401 Lot Pay Factor vs.****Air Voids Required: Example**

**Southwest Region Partnership Conference****March 2006**

## Expected Pay versus Quality LevelsSPONSOR ELECTS 106 % PAY  

**	****	****     ****Expected Pay Factor at Production PWL****	**
**	****Lot Pay     Average in Long Run for n=3 thru n=8**
**PWL****	****Factor    n=3      n=4       n=5       n=6       n=7       n=8  **
**99+****	****106.0****	****106.0****	****106.0****	****106.0****	****106.0****	****106.0****	****106.0****	**
**99****	****106.0****	****105.7****	****105.7****	****105.9****	****105.8****	****105.9****	****105.9****	**
**98****	****106.0****	****105.3****	****105.2****	****105.4****	****105.4****	****105.5****	****105.5****	**
**96****	****106.0****	****104.0****	****104.1****	****104.4****	****104.4****	****104.4****	****104.5****	**
**95****	****105.0****	****103.1****	****103.6****	****103.9****	****103.8****	****103.9****	****104.0****	**
**90 AQL****	****100.0****	****100.1****	****100.2****	****100.8****	****100.8****	****101.0****	****101.0****	**
**85 ****	****  97.5****	****  94.5****	****  96.3****	****  97.4****	****  97.4****	****  97.5****	****  97.6****	**
**80****	****  95.0****	****  89.9****	****  91.3****	****  92.5****	****  92.6****	****  93.0****	****  93.3****	**
**75****	****  92.5****	****  85.4****	****  86.5****	****  87.5****	****  87.7****	****  88.2****	****  88.5****	**
**70****	****  86.0****	****  80.8****	****  81.6****	****  82.1****	****  82.4****	****  82.6****	****  83.0****	**
**65****	****  79.0****	****  76.4****	****  76.7****	****  76.6****	****  76.9****	****  77.0****	****  77.1****	**
**60****	****  72.0****	****  72.1****	****  72.0****	****  71.1****	****  71.6****	****  71.4****	****  71.3****	**
**55 RQL****	****  65.0****	****  68.2****	****  67.7****	****  66.2****	****  66.5****	****  66.0****	****  65.7****	**

**Expected Pay versus Quality Levels****SPONSOR ELECTS 106 % PAY  **

**Southwest Region Partnership Conference****March 2006**

## Expected Pay versus Quality LevelsSPONSOR ELECTS 100 % PAY  

**	****	****     ****Expected Pay Factor at Production PWL****	**
**	****Lot Pay     Average in Long Run for n=3 thru n=8**
**PWL****	****Factor    n=3      n=4       n=5       n=6       n=7       n=8  **
**99+****	****106.0****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	**
**99****	****106.0****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	**
**98****	****106.0****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	**
**96****	****106.0****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	**
**95****	****105.0****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	**
**90 AQL****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	****100.0****	**
**85 ****	****  97.5****	****  94.5****	****  96.3****	****  97.4****	****  97.4****	****  97.5****	****  97.6****	**
**80****	****  95.0****	****  89.9****	****  91.3****	****  92.5****	****  92.6****	****  93.0****	****  93.3****	**
**75****	****  92.5****	****  85.4****	****  86.5****	****  87.5****	****  87.7****	****  88.2****	****  88.5****	**
**70****	****  86.0****	****  80.8****	****  81.6****	****  82.1****	****  82.4****	****  82.6****	****  83.0****	**
**65****	****  79.0****	****  76.4****	****  76.7****	****  76.6****	****  76.9****	****  77.0****	****  77.1****	**
**60****	****  72.0****	****  72.1****	****  72.0****	****  71.1****	****  71.6****	****  71.4****	****  71.3****	**
**55 RQL****	****  65.0****	****  68.2****	****  67.7****	****  66.2****	****  66.5****	****  66.0****	****  65.7****	**

**Expected Pay versus Quality Levels****SPONSOR ELECTS 100 % PAY  **

**Southwest Region Partnership Conference****March 2006**

## Southwest Region Partnership ConferenceMarch 2006

**Southwest Region Partnership Conference****March 2006**

## FAA ACCEPTANCE –Lot  pay equation has an advantage up to 96 PWL

**FAA ACCEPTANCE –Lot  pay equation has an advantage up to 96 PWL**

- Lot-Basis, n=4 sublots per lot.
- Mat Density– Contractor target >=98.5%
- Joint Density – Contractor target >=96.5%
- Air Voids – Contractor target ~ 3.5%
- Strength –Achieve 8.5% Coefficient of Variability or Increase Over design Amount.
- Thickness  -- 3/8” or better.

**Southwest Region Partnership Conference****March 2006**

## Southwest Region Partnership ConferenceMarch 2006

**Southwest Region Partnership Conference****March 2006**

## Southwest Region Partnership ConferenceMarch 2006

**Southwest Region Partnership Conference****March 2006**

## Southwest Region Partnership ConferenceMarch 2006

**Southwest Region Partnership Conference****March 2006**

## Southwest Region Partnership ConferenceMarch 2006

**Southwest Region Partnership Conference****March 2006**

## Workshop Interaction

**Workshop Interaction**

**Southwest Region Partnership Conference****March 2006**

## Workshop Interaction

**Workshop Interaction**

**Southwest Region Partnership Conference****March 2006**

## Southwest Region Partnership ConferenceMarch 2006

**Southwest Region Partnership Conference****March 2006**

## Southwest Region Partnership ConferenceMarch 2006

**Southwest Region Partnership Conference****March 2006**