Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_47 (particulate_size_approaching_100_percentage_retention VARCHAR, usage VARCHAR, class VARCHAR)
### Question:
Which Particulate size approaching 100% retention has a Usage of semi hepa and a Class of h12?
### Answer:
SELECT particulate_size_approaching_100_percentage_retention FROM table_name_47 WHERE usage = "semi hepa" AND class = "h12"