Unless concealed carrying one does not need a CPL to have their firearm secured, note they are required to provide a lock box or a designated official to receive weapons for safe keeping and must be with in the same building.
RCW 9.41.300
Weapons prohibited in certain places — Local laws and ordinances — Exceptions — Penalty.
(1) It is unlawful for any person to enter the following places when he or she knowingly possesses or knowingly has under his or her control a weapon:
(a) The restricted access areas of a jail, or of a law enforcement facility, or any place used for the confinement of a person (i) arrested for, charged with, or convicted of an offense, (ii) held for extradition or as a material witness, or (iii) otherwise confined pursuant to an order of a court, except an order under chapter 13.32A or 13.34 RCW. Restricted access areas do not include common areas of egress or ingress open to the general public;
(b) Those areas in any building which are used in connection with court proceedings, including courtrooms, jury rooms, judge's chambers, offices and areas used to conduct court business, waiting areas, and corridors adjacent to areas used in connection with court proceedings. The restricted areas do not include common areas of ingress and egress to the building that is used in connection with court proceedings, when it is possible to protect court areas without restricting ingress and egress to the building. The restricted areas shall be the minimum necessary to fulfill the objective of this subsection (1)(b).
For purposes of this subsection (1)(b), "weapon" means any firearm, explosive as defined in RCW 70.74.010, or any weapon of the kind usually known as slung shot, sand club, or metal knuckles, or any knife, dagger, dirk, or other similar weapon that is capable of causing death or bodily injury and is commonly used with the intent to cause death or bodily injury.
In addition, the local legislative authority shall provide either a stationary locked box sufficient in size for pistols and key to a weapon owner for weapon storage, or shall designate an official to receive weapons for safekeeping, during the owner's visit to restricted areas of the building. The locked box or designated official shall be located within the same building used in connection with court proceedings. The local legislative authority shall be liable for any negligence causing damage to or loss of a weapon either placed in a locked box or left with an official during the owner's visit to restricted areas of the building.
The local judicial authority shall designate and clearly mark those areas where weapons are prohibited, and shall post notices at each entrance to the building of the prohibition against weapons in the restricted areas;