SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: https://read.dmtmag.com/i/726375
www.stma.org October 2016 | SportsTurf 29 MATERIALS AND METHODS This case study assembles and compares the 20-year life-cycle costs of fi ve natural turfgrass and fi ve synthetic infi ll fi elds in the Willamette Valley, OR. Annual player-use data was collected on these fi elds to create to compare the cost effi ciency of the 10 fi elds over their life cycles. This was accomplished by calculating the cost of providing one hour of use for a single individual [20 year life-cycle cost / (annual hours of individual use * 20 years)]. Surface temperature and hardness data were also collected monthly in 2014- 2015 using the testing procedures found in ASTM F1963—10 standard procedures for fi eld hardness testing and using a FieldScout TruFirm and Raytek non-contact thermometer. In order to represent a broader range of maintenance capabilities fi elds were selected for this study to cover maintenance levels from K-12 schools to the NCAA level. COST OF INSTALLATION The overall average of natural grass athletic fi eld installation, which includes three sand-based fi elds and two native soil fi elds, was $325,000 with a cost per square foot range of $1.50-$6.50. The average cost of installing the fi ve synthetic infi ll fi elds was $1,212,000 with a cost per square foot from $12.50-$20.40. By comparison the average cost of natural grass installation was $887,000 less than the average cost of synthetic fi eld installation. A possible reason for the larger values when compared to the literature is the cost of soil stabilization required for clay soils present at the sites. COST OF MAINTENANCE The average cost of a single year of maintenance for fi ve natural grass fi elds was $35,000 while the average cost of a single year of maintenance for the 10 synthetic infi ll fi elds was $7,000. The average annual maintenance budget for natural grass fi elds was almost fi ve times as much than the average annual maintenance for synthetic infi ll fi elds with a difference of $28,000. Of the fi ve natural grass fi elds only fi eld 1, the university fi eld, is on a schedule to be resurfaced. The cost includes removal of old surface, rolling, topdressing, and seeding. It is planned to be done every 5 years at the cost of $21,000. Re- carpeting of the fi ve synthetic fi elds was planned for all fi elds after 8-10 years. The average cost of re-carpeting synthetic fi elds was $376,000. 20-YEAR BUDGET The average cost of a 20-year maintenance cycle for the fi ve natural grass fi elds was $903,000. The average cost of a 20- year maintenance cycle for the 10 synthetic infi ll fi elds was $1,952,000. The average on synthetic infi ll fi elds was two times as much the average for natural grass fi elds. The calculated individual annual hours for the natural grass fi elds averaged 22,000 hrs. Expanded to the 20-year period the usage-hours were an average of 438,130 hrs. Similarly the synthetic fi elds averaged 22,000 hrs. The average annual hours 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 2 4 6 8 10 12 Inches of Depression Month Natural Grass Monthly Avg. Surface Hardness 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 2 4 6 8 10 12 Inches of Depression Month Synthetic Infill Monthly Avg. Surface Hardness 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 0 2 4 6 8 10 12 Inches of Depression Month Natural Grass Monthly Avg. Surface Hardness 0 0 0.2 0.2 0.4 0.6 0.6 0.8 0.8 1 1 1.2 1.2 1.4 1.6 1.6 1.8 1.8 2 2 2 0 0 0 0 2 4 6 8 10 12 Inches of Depression Month Synthetic Infill Monthly Avg. Surface Hardness