Collection Vehicle Payload and Compaction Ratio
Compares a refuse body's volumetric payload against the chassis's legal payload and reports which governs.
Example
You enter
- Body volume (cy) 25
- Loose waste density (lb/cy) 200
- Packer compaction ratio 3
- Chassis GVWR (lb) 33000
- Tare weight (lb) 21000
- Alternative body volume (cy) 31
- Alternative chassis GVWR (lb) 54000
- Alternative tare weight (lb) 28000
- Wet-weather loose density (lb/cy) 250
You get
- In-body density 600 lb/cy after compaction
- Body payload (ton) 7.5
- Chassis payload (ton) 6
- Legal fill 20.0 cy -- 80% of the body
- Legal fill share (%) 80
- A full body would be 3000
- Overload pct of gvwr 9.09091
- The alternative configuration 9.3
- Alternative chassis payload (ton) 13
- Alternative headroom (lb) 7400
- In wet weather 16
- Wet fill reduction (%) 20
No published worked example is on file for this calculation. It is checked against a hand-worked derivation of its method and an independent reference test.
Details, formula, and sources
ScopeThe legal fill, and the overload a full body would produce. The worked single axle is legal at 80% of its body; specify chassis and body together so the body governs and the crew can fill it.
Formula or tablein-body density = loose density x compaction ratio; body payload = body volume x that density; chassis payload = gross vehicle weight rating - tare weight; the smaller governs, and the legal fill = chassis payload / in-body density.
Source and editionManufacturer ratings against the applicable weight law. Axle-by-axle loading, not just gross weight, is what an enforcement scale checks.
Free accessPublic arithmetic; the ratings come from the chassis and body manufacturers.
What governsEstimate. AHJ and licensed professional govern.
API field namesbody_volume_cy, loose_density_lb_per_cy, compaction_ratio, gvwr_lb, tare_weight_lb, alternative_body_volume_cy, alternative_gvwr_lb, alternative_tare_weight_lb, wet_loose_density_lb_per_cy, in_body_density_lb_per_cy, body_payload_tons, chassis_payload_tons, legal_fill_cy, legal_fill_share_pct, overload_lb, overload_pct_of_gvwr, alternative_body_payload_tons, alternative_chassis_payload_tons, alternative_headroom_lb, wet_legal_fill_cy, wet_fill_reduction_pct
- Axle loading not computed here; gross weight alone does not establish legalityapplicable weight law
- Loose density moves with the weather, so the legal fill moves with it toofacility scale records