Estimating 1000-hour fuel moistures in the Douglas-fir subregion.

Apertures in the cast concrete walls of a swimming pool are lined with tubular inserts entirely received in the apertures in sealing, conforming engagement with the concrete. The length of each insert in the direction of wall thickness is equal to or shorter than the corresponding length of the receiving aperture. The insert essentially consists of a solid mixture of a particulate, rigid, inorganic material, such as quartz sand, and a smaller amount of a more resilient, synthetic organic resin binder. A fastening flange is provided in the bore of the insert for fastening the insert in a form while the wall is being built by pouring fluid concrete mixture into the form. The flange provides a fastening base for later installed fittings, pumps, etc. During construction of the swimming pool, a form bounding a cavity is erected. The afore-mentioned insert is secured in the form by means of the fastening means, and fluid concrete mixture is poured into the form cavity until the insert is enveloped by the concrete mixture. After curing of the concrete mixture, the form is removed.