It seems logical that an entrance mat helps prevent debris from entering a building. As homeowners, we put mats on both the inside and outside of all our doors and it’s become custom in the US to take our shoes off at the door. So exactly how much dirt is stopped at the door, and how does containing the dirt benefit a building owner?
How Much dirt is stopped at the door?
To begin, the outdoor climate must be addressed. A southern beach climate may have fine sand but don’t be fooled into thinking that sand can be removed with a short two or three step system. Sand can wreak havoc on a floors interior, just as the northern snow can.
In order to remove 90% of the debris from foot traffic it is recommended that an entrance system allows for 8 to 9 steps. An average stride is between 24 and 30 inches.
For the calculation purposes we’ll use a 24 inch stride and 9 steps, this equals an 18 foot entrance system.
Yes, an ideal entrance system is 18 feet in length. A system that is 18 feet in length that contains that proper treads for the environment, and proper depth for the traffic, should stop 90% of dirt from entering the building.
- Length of System = Amount of debris removed
- Depth of System = Dependent upon traffic (more traffic, deeper the system)
- Treads on the system = Dependent upon type of debris that needs to be removed
How does an 18 Foot System Save on Maintenance Costs?
Let’s start out with some assumptions that were the results of a 1995 ISSA study:
- Assumption 1 – One thousand people track up to 24 lbs of dirt into a building over a period of a month (We are going to assume that a month consists of 20 workdays)
- Assumption 2 – Average cost to remove One pound of dirt is $500.00
- Assumption 3 – An entrance system that is 18’ in length will remove 90% of dirt.
For 1000 people entering a building 5 days a week that amounts to:
.9 X 24 lbs of dirt =
– 21.6 pounds of dirt removed and retained in the entrance system
– 2.4 pounds of dirt tracked into the building
Annual floor maintenance cost for 1000 people entering a building 5 days a week for one year
No entrance System
– 24 lbs of dirt X $500.00/ lb of dirt X 12 months = $144,000 per year
An ideal entrance system 18’ in length
– 2.4 lbs of dirt X$500.00/ lb of dirt x 12 months = $14,400 per year
For this example the annual savings are $129,600 – That’s sizeable!