Transport, Storage & Handling Stresses
Following four fundamentally different types of stresses/loads exist during transportation, storage and handling of cargo. Packaging needs to be designed taking these stresses into consideration.
Mechanical Stress
Static stresses :
Static stresses are caused by stacking and standing cargo on the floor of the container. The main factor is stacking pressure, causing bending and buckling, particularly in the bottom layers. The stacking pressure depends on the dimensions, weight, shape and height of cargo involved.
Dynamic stresses :
Dynamic stresses can be further classified into 2 categories :
i. Impact Stresses:
Free fall Free fall (dropping), tipping (by exceeding tilting moment), tumbling (rolling edge over edge), bumping (during hoisting, abrupt setting-down or bumping by other cargoes), jolting impacts (during switching), bumping against vehicle walls or other cargo, etc
ii. Vibratory Stresses:
occurs due to the movement of the vehicle/vessel, shaking, chaffing (vehicle running), unevenness of travel way, etc.
Potential acceleration experienced during transportation : Sample acceleration forces on a ship :

Acceleration forces in different modes of transport :
Mode of transport Acceleration acting forwords Acceleration acting backwords Acceleration acting sideways
Road Vechicle 1.0 g 0.5 g 0.5 g
Subject to shunting
Combined (intermodel)
transport *
4.0 g
1.0 g
4.0 g
1.0 g
0.5 g (a)
0.5 g (a)
Batlic Sea **
North Sea **
0.3 g (b)
0.3 g (c)
0.4 g (d)
0.3 g (b)
0.3 g (c)
0.4 g (d)
0.5 g
0.7 g
0.8 g
Tabel 1: Assumed loads as per the Guidelines for Packing of Cargo Trasport Units
*     :   Wagons with the containers, swap-bodies, semi-trailers and truck and also "block trains" (UIC and RIV)
**   :   Primarily feery trafic and container feeder services
The values given above must be combined with the downword force of gravity of 1 g and any dynbamic fluctuations (vertical) as follows :
(a) = +- 0.3 g      (b) = +- 0.5 g       (c) = +- 0.7 g       (d) = +- 0.8 g
Climatic Stress
Climatic stresses act on the packages throughout the entire duration of transport and storage. The impact on the cargo due to climatic loads is dependent on the following three major factors:
i.  External climatic conditions
    a. Temperature
    b. Humidity
    c. Dew Point Temperature
    d. Temperature/Dew Point Difference
ii. Nature of Cargo (mass of the cargo, exposed surface area, hygroscopic nature of cargo, etc)
iii.Type of container (standard containers, passively ventilated containers, refrigerated containers, etc)
Biotic Stress : (biotic - derived from living organisms)
High temperatures, moisture or poor ventilation in the container can lead to cargo or packaging being attached by insects, fungi, mould, bacteria or micro-organisms. Sometimes the cargo is biologically contaminated even before it is loaded into the container. Hence some countries regulate the fumigation of packaging and dunnage by low. We at Hirji Packers & Suppliers strictly follow the ISPM 15 guidelines.
Chemical Stress
Chemical loads depend on the type of cargo, temperature, moisture and movement of the ship. Some chemical products tend to heat spontaneously. Hazardous goods must be transported in accordance with the hazardous goods regulations. One basis is the IMDG Code, published by the International Maritime Organisation.