SASO S TANDAR D SASO/FDS 31843/2020
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واﻟ واﻟ  ﻟﻠ  اﻟ  اﻟﻬ 
Saudi Standards, Metrology and Quality Org. (SAS O) 
 
      
 
 
 
 
 
Final Draft Standard  
 
  
 
SASO /FDS/31843/2020  
  
 
 
School buses – Rear crash test using moving barrier 
 
   
 
ICS: 43.020 
 
This document is a draft Saudi Standard circulated for comments . It is, therefore, 
subject to alteration and modifi cation and may not be referred to as a Saudi 
Standard until approved by SASO . SASO S TANDAR D SASO/FDS 31843/2020
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Conte nts 
 
1- Scope and field and application  ............................................................. ........................... 3 
 
2- Complementary references .............................................................. .................................. 3 
 
3- Terms and definitions  .............................................................. ............................................ 3 
 
4- Test conditions  .............................................................. ......................................................... 3 
 
5- Technical requirements  ............................................................... ....................................... 4 
 
6- Test requirements  ............................................................... ................................................ 4 
 
 
Bibliography   ............................................................. ............................................................... .. 7 SASO S TANDAR D SASO/FDS 31843/2020
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 School buses – Rear crash test using moving barrier 
 
1- Scope and field of the appl ication 
This standard specifies the technical requirements for the inte grity of school buses fuel system 
by rear crash test using the moving barrier. 
 
This standard applies to school buses with gross vehicle weight  rating (GVWR) greater 
than 4500 kg. 
 
2- Complementary references 
2.1 ASTM D235 "Standard Specification for Mineral Spirits (Petrole um Spirits) (Hydrocarbon 
Dry Cleaning Solvent)". 
2.2 ASTM E274/E274M "Standard Test Method for Skid Resistance of P aved Surfaces Using 
a Full-Scale Tire". 
 
3- Terms and definitions 
For the purposes of this standard, the following terms and defi nitions are applied: 
3.1 School bus 
A specially constructed vehicle that is designed to carry more than ten persons to and from 
school, university or related events. 
3.2 Fuel spillage 
The fall, flow, or run of fuel from the vehicle but does not in clude wetness resulting from 
capillary action. 
3.3 Gross vehicle weight rating (GVWR)  
The value specified by the vehicle manufacturer as the load- ca rrying capacity of a single 
vehicle, as measured at the tire-ground interfaces. 
 
4- Test condi tions 
The following conditions apply to test: 
4.1 Test vehicle 
4.1.1  The fuel tank is filled to any level from 90 to 95 % of capaci ty with Stoddard solvent, 
having the physical and chemical properties of type (1) solvent , Table I of ASTM D235. 
4.1.2  The fuel system other than the fuel tank is filled with Stodda rd solvent to its normal 
operating level. 
4.1.3  The parking brake is set and the transmission is in neutral. 
4.1.4  Tires are inflated to manufacturer's specifications. 
4.1.5  A school bus with a GVWR greater than 4,500 kg is loaded to it s unloaded vehicle weight, 
plus 54 kg of unsecured mass at each designated seating positio n. 
4.2 Moving barrier 
4.2.1  The moving barrier shall be mounted on a carriage and rigid co nstruction, symmetrical 
about a vertical longitudinal plane as specified in Figure (1).  
4.2.2  The moving barrier has a solid non steerable front axle and fi xed rear axle attached directly 
to the frame rails with no spring or other type of suspension s ystem on any wheel. SASO S TANDAR D SASO/FDS 31843/2020
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4.2.3  The moving barrier is equipped with a braking device capable o f stopping its motion. 
4.2.4  The barrier assembly is released from the guidance mechanism i mmediately prior to 
impact with the vehicle. 
4.2.5  The total weight shall not exceed 1,814 ± 23 kg distributed so  its front and rear axles so 
that their loadings are: 
At each front wheel: 499 ±11 kg 
At each rear wheel: 408 ±11 kg 
4.2.6  The height of the impact surface of the barrier shall be 629 m m and its width 1,981 mm, 
as specified in Figure (2). 4.2.7  The center of gravity is 1,372 ± 38 mm rearward of the front w heel axis, in the vertical 
longitudinal plane of symmetry, 401 ± 13 mm above the ground. 
4.2.8  The ground clearance to the lower edge of the impact surface i s 133 ± 13 mm. 
4.2.9  The wheelbase is 3,048 ± 50 mm. 
4.2.10 The barrier assembly is released from the guidance mechanism im mediately prior to 
impact with the vehicle. 
4.2.11   The  moving  barrier  is  equipped  with  P  205/75  R  15  p neumatic  tires  inflated 
to 200 ±21 kPa. 
4.3 Test 
site 
4.3.1  The test site shall be of sufficient area to provide for accom modation of the instruments, 
and for the attaining of the desired velocity by the moving bar rier. 
4.3.2  The concrete surface upon which the vehicle is tested is level , rigid, and of uniform 
construction, with a skid number of 75 when measured in accorda nce with ASTM E274/E274M 
and at least 15 m long, and shall not slope from the horizontal  by more than 3o over any one- 
meter length of the path of the moving barrier. 
 
5- Technical requirements 
5.1 Fuel spillage in any moving barrier crash test shall not excee d 28 g from impact until motion 
of the vehicle has ceased, and shall not exceed a total of 142 g in the 5-minute period following 
cessation of motion. For the subsequent 25-minute period, fuel spillage during any 1-minute 
interval shall not exceed 28 g. 
 
6- Test requirements 
6.1 Fuel spillage shall not exceed the limits of 5.1 when the movi ng barrier traveling 
longitudinally forward at any speed up to and including 48 km/h  impacts the test vehicle at any 
point and angle, under the applicable conditions of 4. 
  
 
  
 SASO S TANDAR D SASO/FDS 31843/2020
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NOTES: 
1- Outer frame (152 × 51 × 5 mm)  steel tubing. t wo pieces welde d together for (305 mm) height. 
2- Ballast tie downs. 
3- All inner reinforcements and frame cusses of (102 × 51 × 5 m m) steel tubing. 
4- Reinforced areas for bolting on face plates.   
Figure (1) – Common carri age for moving barriers 
 
SASO S TANDAR D SASO/FDS 31843/2020
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NOTES: 
1- Upper frame (102 DIA × 6 mm wall) steel tubing (three sides). 
2- Lower frame (152 DIA × 13 mm wall) steel tubing. 
3- Face plate (19 mm) thick cold rolled steel. 
4- Leading edge (25 × 102 mm wall) steel band, sharp edges broken. 5- All inner reinforcements (102 × 51 × 5 mm) steel tubing. 
 
Figure (2) – Common carriage wi th impact surf ace attached 
 
SASO S TANDAR D SASO/FDS 31843/2020
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Bibliography  
 
- The main reference: 
[1] 49 Subtitle B-Chapter V-Part 571-Subpart B Section 301 
(FMVSS 571.301)  “Fuel system integrity”.