Freestanding emergency rooms took center stage at a certificate of need hearing Wednesday, underscoring how interested health systems are in expanding their footprint. Freestanding ERs are the newest battle in health system turf wars — and they are showing up for state approval with greater frequency. Eight had been voted on, and half of that number approved, by the Health Services and Development Agency over the years. The agency heard two in September and two in March. After four applications were heard on Wednesday, the tally comes to 12, with decisions on the freestanding ERs roughly 50-50 — six approvals, five denials and one deferral.